JANESVILLE, Wis. -- There are plenty of reasons for Republican presidential candidate Mitt Romney to choose Rep. Paul Ryan as a running mate.

The whip-smart Wisconsin congressman is from a battleground state. He's the GOP's leading voice on the nation's budget and is the rare member of the Republican establishment who's loved by the tea party.

"If that bridge ever came, I would consider crossing it," Ryan told The Associated Press in an interview this month. He added: "I really don't have tremendous political ambition. I have policy ambition."

Yes, that's the typical humble-speak of someone who's a potential vice presidential candidate. But it's also true that Ryan has let political opportunities pass before, choosing to focus on taming what he calls a "big, dysfunctional government" beset by unsustainable spending.

Those who know Ryan say that means that while Romney ponders whether to ask, Ryan is deciding whether accepting a political promotion is the best way to achieve his "policy ambition."

"He does have more force and authority than he would have in the vice presidency. I think he clearly knows that," said Vin Weber, a former Minnesota congressman and Ryan's supervisor when the two were at a Washington think tank in the 1990s. "So the question becomes, Would that be worth sacrificing to put yourself clearly in line to be the nominee after Romney?"

Romney planned to appear with Ryan on Monday during a visit to a fabric mill in the congressman's hometown of Janesville, a blue-collar city along the Rock River still coping with the mothballing of a GM assembly plant a few years ago.

The ascent has been swift for Ryan, who was voted prom king and the "Biggest Brown-Noser" of his 1988 high school class before leaving for college in Ohio. He maintained his ties to home through summer internships for Republican Sen. Robert Kasten, who later hired Ryan full time. The former senator remembers him as "bright and inquisitive and very consumed" with complex tax policy.

Ryan went on to flourish at a conservative policy institute founded by Republican Jack Kemp. A congressman, a member of the George H.W. Bush administration and GOP presidential nominee Bob Dole's running mate in 1996, Kemp championed tax cuts as the primary tool for promoting economic growth. Ryan considers Kemp, who died in 2009, his mentor.

By 28, Ryan was back in Janesville winning election to Congress. At 42, he is among the breed of congressmen who sleep in the office rather than put down roots in Washington.

Heavy with both factories and farms, Ryan's district in southern Wisconsin is typically carried by Democratic presidential candidates. His opponents note that part of his success lies in the overtures he makes across the aisle, from party-bucking votes against weakening prevailing wage laws to simpler gestures, like his recent attendance at a wake for the father of a local Democratic stalwart.

Prone to speaking in bar graphs as he warns of "a gathering storm" of debt that will challenge America's way of life, Ryan has also mastered the ability to hang a smile on ideas that generations of politicians have found treacherous.

He casts his push to scale back food stamps and other welfare assistance as empowerment for the downtrodden now lulled into complacency. Opening Medicare to more private competition, he argues, is about preventing an all-out program collapse that would devastate future retirees.

"He's a master politician," said former Wisconsin Democratic Party Chairman Joe Wineke. "I don't have a mean thought in my body about Paul. I just fundamentally disagree with his policies. He puts on a good face for some pretty awful policies."

The global economic crisis and the rise of the tea party, with its focused attention on government spending and debt, have made Ryan's budget plans something of a GOP litmus test. In March, Romney was quick to praise Ryan's latest proposal to slice trillions from the federal budget. Ryan reciprocated soon after with an endorsement of Romney's White House bid.

Picking Ryan as his running mate would be read as a full embrace of his budget ideas. But that assumes Ryan would return Romney's interest.

During President George W. Bush's second term, Ryan pulled his name from consideration for the White House budget director post. He says he didn't think there was the will, particularly in Congress, to address the structural budget changes he believes are needed to avert a crippling debt crisis.

"There were no followers," he said.

More recently, Ryan resisted a call to chase an open Senate seat in Wisconsin. "I didn't want to walk away from the conversation I started and the fight I'm in," he said. By remaining in the House, Ryan can keep an intense focus as budget chairman on his signature issue – something he might not be able to do in a Romney administration.

There's no guarantee that Republicans will retain House control in November or that even with Romney in the White House, Ryan could help accomplish an overhaul of venerable but politically sensitive programs such as Medicare and Social Security.

It's a gamble either way.

"I think I'm in a really big spot right now," he said.

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  • Bob McDonnell

    <strong>Who:</strong> Virginia Gov. Bob McDonnell (R) <strong>The Buzz:</strong> McDonnell <a href="http://www.huffingtonpost.com/2012/01/20/bob-mcdonnell-mitt-romney-endorsement_n_1218559.html" target="_hplink">endorsed Mitt Romney</a>, the only candidate besides Ron Paul to make it on his state's ballot, and Romney <a href="http://www.politico.com/news/stories/0711/59933.html#ixzz1TJCfqwQ4" target="_hplink">said last summer </a>that McDonnell would be on "any candidate's short-list" as a VP pick. Rep. Tim Scott (R-S.C.)<a href="http://goosecreek.patch.com/articles/veep-speculation-greets-mcdonnell-in-s-c" target="_hplink"> has already started referring </a>to McDonnell as "Mr. Vice President." <strong>His Response:</strong> McDonnell said on "Meet The Press" in March that he wasn't interested in the position. "I've got the job held by Jefferson and Henry," <a href="http://www.washingtonpost.com/blogs/maryland-politics/post/martin-omalley-touts-bob-mcdonnell-for-vice-president-kind-of/2012/03/11/gIQATP6I5R_blog.html" target="_hplink">he said</a>. "I love being governor of Virginia."

  • Chris Christie

    <strong>Who:</strong> New Jersey Gov. Chris Christie (R) <strong>The Buzz:</strong> Christie <a href="http://www.huffingtonpost.com/2011/09/04/chris-christie-president-2012_n_948401.html" target="_hplink">fielded numerous calls</a> to run in 2012, and is now attracting speculation as a possible VP pick by Mitt Romney, who called Christie, "one of the leading figures in the Republican party." <strong>His Response:</strong> Christie didn't do much to quell the rumors in December when he <a href="http://www.huffingtonpost.com/2011/12/23/chris-christie-vice-president-mitt-romney_n_1167557.html" target="_hplink">addressed them</a> by saying: <blockquote>I don't think you talk about that stuff. I think if you're the nominee you're afraid to talk about that stuff because you don't want to jinx yourself. I don't think [Romney] wants to be presumptuous enough to start talking to somebody about a vice president when he's not yet the nominee.</blockquote>

  • Marco Rubio

    <strong>Who:</strong> Florida Sen. Marco Rubio (R) <strong>The Buzz:</strong> Newt Gingrich <a href="http://www.huffingtonpost.com/2012/01/30/newt-gingrich-marco-rubio_n_1242912.html" target="_hplink">called Rubio</a> an "awfully good" choice, while Mitt Romney named him as an obvious choice for the short-list. As the Huffington Post's Carlos Harrison <a href="http://www.huffingtonpost.com/2012/02/02/marco-rubio-tea-party_n_1249480.html?ref=gingrich-2012" target="_hplink">reported</a>, "He's the posterboy for a demographic coveted by the GOP: a telegenic Tea Party favorite and a Latino. And despite being both young and a freshman among Washington, D.C., power brokers, he exerts outsized influence." <strong>His Response:</strong> Rubio himself <a href="http://abcnews.go.com/blogs/politics/2011/10/i-am-not-going-to-be-the-vp-nominee/" target="_hplink">seems less enthusiastic</a>: <blockquote>When asked at the Washington Ideas Forum at the Newseum in Washington DC, Rubio repeated twice for emphasis, "I am not going to be the Vice Presidential nominee. I am not going to be the Vice Presidential nominee." Asked during the forum if he would turn down an offer if the Republican presidential nominee asks him to, Rubio responded, "Yea, I believe so," adding again, "the answer is gonna be no."</blockquote>

  • Brian Sandoval

    <strong>Who:</strong> Nevada Gov. Brian Sandoval (R) <strong>The Buzz:</strong> Ahead of the Nevada caucus, Sandoval <a href="http://2012.talkingpointsmemo.com/2012/02/could-mitt-romney-pick-up-a-vp-in-nevada.php" target="_hplink">was speculated</a> to be a potential VP pick: <blockquote>Nevada's governor Brian Sandoval has been bandied about as a potential -- if longshot -- veep choice since his election in 2010. On paper, his resume looks solid. He's a young rising star in the party with strong approval ratings and, as a Hispanic Republican, could help a Republican nominee -- and especially Romney -- stop the bleeding with one of the party's weakest general election demographics. </blockquote> While no candidates have floated his name for VP yet, Mitt Romney <a href="http://www.lasvegassun.com/news/2012/jan/26/mitt-romney-mentions-brian-sandoval-cabinet-possib/" target="_hplink">did mention him</a> as a possible Cabinet member. <strong>His Response:</strong> After endorsing Rick Perry last September, Sandoval <a href="http://latino.foxnews.com/latino/politics/2011/09/16/nevada-gov-brian-sandoval-wont-be-rick-perrys-vice-presidential-pick/" target="_hplink">denied that he was looking for a VP nod</a>. "I am absolutely committed to serving out my term," he said.

  • Nikki Haley

    <strong>Who:</strong> South Carolina Gov. Nikki Haley (R) <strong>The Buzz:</strong> Haley's endorsement of Mitt Romney <a href="http://www.huffingtonpost.com/2012/01/22/nikki-haley-romney_n_1221682.html" target="_hplink">didn't do him much good</a> in the state, but her name has still come up as a possible candidate for VP. <strong>Her Response:</strong> "I'd say, 'Thank you, but no,'" <a href="http://abcnews.go.com/Politics/News/south-carolina-gov-nikki-haley-shed-turn-vp/story?id=16050396#.T3nGGCvLx1Z" target="_hplink">Haley told ABC News</a>. "I made a promise to the people of this state. And I think that promise matters. And I intend to keep it."

  • Susana Martinez

    <strong>Who:</strong> New Mexico Gov. Susana Martinez (R) <strong>The Buzz:</strong> Martinez has attracted attention as the first female Hispanic governor, and Mitt Romney <a href="http://latino.foxnews.com/latino/politics/2012/01/23/new-mexico-gov-susana-martinez-says-no-thanks-to-mention-her-as-possible-romney/" target="_hplink">mentioned her</a> as a good possible running mate. <strong>Her Response:</strong> Martinez <a href="http://thehill.com/blogs/blog-briefing-room/news/205571-nm-governor-not-interested-in-vp-spot" target="_hplink">has said</a> she's flattered, but not interested: <blockquote>"She has no interest in serving as vice president and will not be a candidate for the position," Martinez spokesman Scott Darnell said in a statement according to the Santa Fe New Mexican on Friday. </blockquote>

  • Haley Barbour

    <strong>Who:</strong> Former Mississippi Gov. Haley Barbour (R) <strong>The Buzz:</strong> Barbour was considered a promising candidate for the 2012 nomination until he <a href="http://www.huffingtonpost.com/2011/04/25/haley-barbour-2012-presid_n_851969.html" target="_hplink">decided not to run</a> last summer. Mitt Romney has mentioned Barbour as a name <a href="http://www.examiner.com/charleston-democrat-in-charleston-sc/romney-names-possible-vp-candidates" target="_hplink">he'd consider</a> for vice president. <strong>His Response:</strong> Barbour wouldn't turn down the possibility of being VP, but he said he didn't anticipate being asked. "I don't think I'm a good running mate for anybody, but I do think Marco Rubio would be very attractive as would other people," <a href="http://foxnewsinsider.com/2011/11/07/mississippi-gov-haley-barbour-on-whether-he-would-consider-being-a-vp-pick-in-2012/" target="_hplink">he told FOX last November</a>.

  • Mitch Daniels

    <strong>Who:</strong> Indiana Gov. Mitch Daniels (R) <strong>The Buzz:</strong> Daniels hasn't endorsed a candidate yet, but he's considered a potential pick for the VP slot. His book, "Keeping the Republic: Saving America by Trusting Americans," <a href="http://www.realclearpolitics.com/articles/2011/09/19/mitch_daniels_stirs_vp_buzz_with_new_book_111382.html" target="_hplink">added to the hype</a>. <strong>His Response:</strong> Daniels was asked about the possibility <a href="http://www.huffingtonpost.com/2011/09/30/2012-gop-vice-presidential-candidate_n_988558.html" target="_hplink">last fall</a>: <blockquote>"There's no answer to this question," Daniels said when the vice president's job came up while he was promoting his book. He said he'd have to consult his family, which earlier vetoed the idea of him running for president.</blockquote>

  • Jan Brewer

    <strong>Who:</strong> Arizona Gov. Jan Brewer (R) <strong>The Buzz:</strong> Brewer made headlines for a <a href="http://www.huffingtonpost.com/2012/01/30/jan-brewer-pac-obama-fundraiser_n_1241794.html" target="_hplink">confrontation with President Barack Obama</a> at an airport in Phoenix. Does Brewer want another chance to take on the Obama administration? The <a href="http://www.azcentral.com/news/election/azelections/articles/2011/10/16/20111016brewer-vice-president-hopeful.html" target="_hplink">Arizona Republic</a> reports that her name has surfaced as a possible VP candidate. <strong>Her Response:</strong> None so far.

  • Tim Pawlenty

    <strong>Who:</strong> Former Minnesota Gov. Tim Pawlenty (R) <strong>The Buzz:</strong> Pawlenty was a short-lived presidential candidate, quitting in the summer after a third-place finish in the Iowa straw polls. He later endorsed Mitt Romney, who named him as a <a href="http://www.examiner.com/charleston-democrat-in-charleston-sc/romney-names-possible-vp-candidates" target="_hplink">possible VP candidate</a>. <strong>His Response:</strong> Pawlenty <a href="http://www.huffingtonpost.com/2012/02/24/tim-pawlenty-mitt-romney-vice-president_n_1299377.html" target="_hplink">said in an interview</a> that he'd taken himself "off the list" to be considered as Romney's VP.

  • Rob Portman

    <strong>Who:</strong> Sen. Rob Portman (R-Ohio) <strong>The Buzz:</strong> Portman is a supporter of Mitt Romney. In December, his home state's <em>Dayton Daily News</em><a href="http://www.daytondailynews.com/news/politics/portman-still-viable-as-vp-nominee-1301194.html" target="_hplink"> ran an article</a> touting his chances to become VP: <blockquote>His deep resume and absence of political negatives keep him in the discussion as a vice-presidential candidate. "I would be very surprised if the eventual nominee doesn't have Rob on the short list,'' said Tony Fratto, who served as White House press secretary to former President George W. Bush.</blockquote> <strong>His Response:</strong> Portman is noncommittal about being on anyone's presidential ticket. "I truly am not seeking that," he said in an interview with the Dayton Daily News' Washington Bureau.

  • Bobby Jindal

    <strong>Who:</strong> Louisiana Gov. Bobby Jindal (R) <strong>The Buzz:</strong> Jindal, <a href="http://www.huffingtonpost.com/2011/09/12/bobby-jindal-rick-perry-endorsement-2012_n_959162.html" target="_hplink">who endorsed Rick Perry</a>, has seen his star fade <a href="http://www.huffingtonpost.com/2009/02/25/bobby-jindal-response-pan_n_169710.html" target="_hplink">since his widely panned State of the Union response</a> in 2009. But he is still viewed as a potential pick. Florida Gov. Rick Scott (R) <a href="http://miamiherald.typepad.com/nakedpolitics/2011/11/gov-scott-bobby-jindal-would-be-a-great-vp.html" target="_hplink">praised him</a>, saying, "He's well-liked. He's a nice person to deal with. He clearly cares about people. He's willing to make tough choices," Scott said. "So I think he would make a great vice president." <strong>His Response:</strong> "I don't want a job from Governor Perry," Jindal <a href=" http://blog.chron.com/rickperry/2011/09/bobby-jindal-wont-be-rick-perrys-vp-but-says-hes-a-great-neighbor/" target="_hplink">said after endorsing the former candidate</a>. "I want Governor Perry to create millions of jobs for my fellow Americans."

  • John Thune

    <strong>Who:</strong> Sen. Jon Thune (R-S.D.) <strong>The Buzz:</strong> Thune, <a href="http://www.huffingtonpost.com/2011/02/22/john-thune-2012-not-running-for-president_n_826582.html" target="_hplink">once viewed</a> as a potential 2012 candidate himself, has <a href="http://www.huffingtonpost.com/2011/11/23/mitt-romney-john-thune-endorsement_n_1109456.html" target="_hplink">since endorsed Mitt Romney</a>. <strong>His Response:</strong> Thune has said he's not interested in the VP role, but<a href="http://www.kcautv.com/story/16449478/south-dakota-senator-john-thune-not-interested-in-vp-race" target="_hplink"> he wouldn't rule anything out</a>.

  • Kelly Ayotte

    <strong>Who:</strong> Sen. Kelly Ayotte (R-N.H.) <strong>The Buzz:</strong> Ayotte was an early supporter of Mitt Romney. He gave her an endorsement of his own, <a href="http://www.huffingtonpost.com/2011/11/22/mitt-romney-kelly-ayotte_n_1108125.html" target="_hplink">naming her</a> as a possible pick for vice president. <strong>Her Response:</strong> Ayotte said she was "surprised" by Romney's comment, but that "certainly it was an honor to be mentioned." "I am very committed to representing New Hampshire," she <a href="http://www.unionleader.com/article/20111130/NEWS0605/711309959" target="_hplink">told the <em>New Hampshire Union Leader</em></a>. "It is such a privilege to serve New Hampshire in the U.S. Senate."

  • Sam Brownback

    <strong>Who:</strong> Kansas Gov. Sam Brownback (R) <strong>The Buzz:</strong> Brownback endorsed Rick Perry for president, <a href="http://www.kansas.com/2011/09/23/2029027/brownback-endorses-perry-for-president.html" target="_hplink">prompting speculation</a> that he could be looking for a spot as vice president. Brownback also briefly ran for president in 2008. <strong>His Response:</strong> During the last election cycle, Brownback <a href="http://www.huffingtonpost.com/2008/03/13/brownback-would-be-honore_n_91341.html" target="_hplink">said he'd be "honored"</a> to serve as John McCain's vice president. He hasn't yet commented this time around.

  • Allen West

    <strong>Who:</strong> Rep. Allen West (R-Fla.) <strong>The Buzz:</strong> West has been named as a strong contender by a number of his peers, including Herman Cain, <a href="http://livewire.talkingpointsmemo.com/entries/herman-cain-endorses-allen-west-for-vice-presdient" target="_hplink">who called him an "excellent choice"</a>, and Nikki Haley, <a href="http://www.huffingtonpost.com/2012/04/05/nikki-haley-allen-west_n_1405401.html" target="_hplink">who said he would make a "good" pick</a>. <strong>His Response:</strong> "Yes, well, right now, you know, the focus is, of course, being a good congressional representative," <a href="http://www.realclearpolitics.com/video/2012/04/06/allen_west_i_would_say_yes_to_vp_slot_on_gop_ticket.html" target="_hplink">West told CNN's Kyra Phillips</a>. "But if someone were to make that call to me, which I really doubt is ever going to happen, you would have to make sure that it is something that god would ordain for you, and you'd have to talk to your wife, my wife and my two daughters about. But we have always stepped up to the plate to serve our country. And if it's the right fit, then I will do so."