By STEVE PEOPLES, THE ASSOCIATED PRESS

WASHINGTON -- Mitt Romney is staying mum on whether Florida Sen. Marco Rubio, a rising star in Republican politics, has been cut from his short list of potential running mates.

The presumptive GOP presidential nominee told Fox News on Tuesday that "a number of people are being vetted," but that only two people - he and a senior adviser - know who's on the list.

"Even Ann doesn't know," Romney said of his wife. "We talk about the possible people that I might select. But in terms of actually who is being vetted, that is something only two people know. And Beth Myers doesn't talk."

The comments came amid reports by ABC News and The Washington Post that the charismatic Rubio isn't being vetted for vice president. The news distracted from Tuesday's release of Rubio's memoir and the final day of Romney's six-state bus tour, which ended in Michigan Tuesday.

The Florida Democratic Party pounced on the flap, blasting a message to reporters titled: "Rubio fails preliminary review in Veepstakes."

Asked about the reports during an appearance on Fox News, Rubio also refused to weigh in.

"I'm not commenting on the vice presidential process," he said. "That's been basically what we've said the whole time because, out of respect for Gov. Romney, the last thing he needs is to have to be addressing questions about this because really the campaign's not about that."

Rubio's exclusion from Romney's short list would disappoint some conservative activists, but would not come as a complete surprise.

While he offers obvious political benefits as a Hispanic leader from the swing state of Florida, Romney advisers have consistently said that he would give preference to those candidates with the greatest experience and ability to lead the nation on Day One. It's a reflection both of Romney's philosophy and lessons from the selection of former Alaska Gov. Sarah Palin four years ago as the GOP running mate.

A former state lawmaker, Rubio, 41, has served in the Senate for less than two years.

Inexperience also works against other oft-mentioned candidates, including New Hampshire Sen. Kelly Ayotte and New Jersey Gov. Chris Christie.

A handful of more likely picks have joined Romney on his bus tour in recent days as part of unofficial public tryouts for the No. 2 spot. Their interactions offered clues about who Romney might choose.

Former Minnesota Gov. Tim Pawlenty traveled on Romney's bus with him for two full days, on Friday in New Hampshire and through Saturday in Pennsylvania. He often warranted his own introduction, with a local official talking up his accomplishments as Minnesota governor before Pawlenty took the stage to introduce Romney.

When Pawlenty left the tour, it was to fly to New York to appear as a surrogate for Romney on ABC's "This Week."

On Sunday, Ohio Sen. Rob Portman and his wife, Jane, went along for the ride. By this time, though, Romney had been joined by a pack of family members - sons Craig and Matt, and five grandchildren. That left Portman and his wife riding on a different bus from Romney's for part of the day.

Still, Romney's team trusted Portman to talk to the reporters who travel with the likely Republican presidential nominee. A Portman aide snapped BlackBerry photos as the senator did a background briefing.

Least visible was Wisconsin Rep. Paul Ryan, whose role was limited to introducing Republican National Committee Chairman Reince Priebus at an event at a factory in Ryan's hometown of Janesville. Wisconsin Gov. Scott Walker, whose June 5 recall election victory was a big win for Republicans, introduced Romney and accompanied him on a tour through the factory.

Romney's Boston headquarters has been engaged for weeks in the secretive process of weighing the pros and cons of each potential pick.

With less than three months to go until Republican National Convention in August, the campaign has little time to waste as it meticulously prepares the presumptive Republican nominee to make one of his most important decisions. Advisers concede that Romney could make his pick earlier than right before the convention to help boost fundraising efforts.

Knowledge of the process is limited to a few of Romney's highest-level aides. Information is on a "need-to-know" basis - and as far as those aides are concerned, there are few people inside the Boston headquarters who need to know, let alone reporters and other outsiders.

The process is so secret because it's so sensitive.

A vice presidential vetting is possibly the most intense background check in politics. Everything is fair game: voting records and the political past, to be sure, but also personal issues.

"I think everyone should take a deep breath," Rubio said Tuesday. "Here's the one thing everyone should know: Gov. Romney's going to make a great choice. In that I'm confident."

___

Associated Press writer Kasie Hunt contributed to this report.

Loading Slideshow...
  • 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."

Also on HuffPost: