WASHINGTON -- In April of this year, Mitt Romney's presidential campaign had a devil of a time explaining what exactly the presumptive Republican nominee's position was on the Lilly Ledbetter Act, the first bill signed into law by President Obama.

At first, aides to the Massachusetts Republican said they'd get back to reporters with respect to the bill, which expanded the timeframe to bring forward equal pay lawsuits. Eventually, the campaign clarified that Romney was "not looking to change current law" -- a line that suggested he supported it now but didn't explain whether he would have signed it to begin with.

The Lilly Ledbetter Act has since receded as a campaign issue. But with the selection of Rep. Paul Ryan as Romney's vice presidential nominee, it has the potential to once again resurface. The Wisconsin Republican's position on the bill isn't vague. He voted against the measure when it came to the House floor in January 2009.

A Lexis-Nexis search of statements Ryan might have made on the bill came up blank. And an email request for comment to Ryan's current (deluged) campaign press secretary wasn't immediately returned. But at least several Democrats independently told The Huffington Post that they planned to hammer this vote in the days and weeks of campaigning ahead.

The policy disagreements between Romney and Ryan are mostly defined in shades of gray, rather than black and white. The two find symmetry on the broad issues: a desire to slash government spending, revamp entitlements, keep defense spending high and pursue tax cuts that would disproportionately help the rich. But there are some areas -- beyond their current take on the Lilly Ledbetter Act -- in which they've found themselves in opposition.

Take for instance the subject of prevailing wage law -- a pet peeve of many conservatives.

Established by the Davis-Bacon Act during the Great Depression, prevailing wage laws require that companies bidding to work on public projects pay certain minimum wages to the workers they will employ. Unions argue that prevailing wage laws assure that companies won't take public money and then pay below-market rates or use cheaper labor from outside the area; conservatives tend to argue that prevailing wage laws inflate the costs of public projects and merely benefit unions.

Republicans have long sought to repeal Davis-Bacon, and it was Romney himself who tried to make a campaign issue out of the law earlier in the campaign season. The former Massachusetts governor lambasted former Sen. Rick Santorum for voting in support of Davis-Bacon, claiming the law was costing American taxpayers "$100 billion over 10 years." Romney also told a crowd of Michigan voters in February that one of his first orders of business on "day one" of his presidency would be to "fight to repeal Davis-Bacon."

If Romney wants to do that, he may have to persuade his new running mate. In what was something of a coup for construction unions, Ryan was one of 48 Republicans who joined House Democrats last year in voting to uphold Davis-Bacon, defeating a GOP attack on what labor activists consider bedrock legislation. The vote burnished Ryan's reputation among unions back in Wisconsin, with one carpenters' union local saying that Ryan has "supported us on every Davis-Bacon vote that's been held out there."

As Mother Jones noted last year, Ryan's support for Davis-Bacon may have a lot to do with his family construction business, which presumably works closely with local building trade unions. According to James Sherk, a senior labor policy analyst at the conservative Heritage Foundation, the Republicans who vote in favor of Davis-Bacon tend to come from the Midwest, like Ryan, or the Northeast, where there are strong union constituencies. "Obviously, he has taken a number of votes supporting [Davis-Bacon] that we consider bad policy," Sherk told HuffPost in an email.

There may be some dissonance between Romney and Ryan on unions more generally. Whereas Romney has tried to carve out a strong stance against labor on the trail -- even blaming unions for "disappearing industries and disappearing jobs" -- Ryan has spoken more sympathetically of organized labor. "A lot of conservatives just think unions are nothing but bad. That's just not true," Ryan said in 2009, according to the Milwaukee Journal Sentinel. "They're people who are just trying to make their lives better, people trying to collectively negotiate a better standard of living for themselves. What the heck is wrong with that?"

Regional politics have compelled Ryan to take other positions that may not jive with a Romney presidential campaign. Ryan supported the auto-bailout, for instance, at the same time that Romney was writing op-eds calling for Detroit to go bankrupt. Meanwhile, in May 2008, Ryan told a local interviewer that he wanted to take the money that the federal government would gain from taxing expanded oil drilling operations and use it for incentivizing alternative energy production.

"There is a tax break for wind, solar, and biomass, I support those tax incentives," he said.

Ryan may have evolved on that position. His budget calls for "eliminating welfare for energy companies," which has led experts to believe that wind power will lose its tax breaks. But as Ryan has yet to fill in the details, that's just speculation; whereas the Romney campaign has definitively declared it would eliminate the tax incentive.

Similarly, Ryan's budget calls for the elimination of all federal funding for the Corporation for National and Community Service, which funds national service programs like AmeriCorps. But in 1995, as a board member of City Year, Romney joined with President Bill Clinton and condemned GOP lawmakers' proposals to abolish federal funding for AmeriCorps.

Perhaps the biggest disagreement between Romney and Ryan, however, came on one of the biggest legislative issues of the past two years. When Congress and the White House came to an agreement to extend the debt ceiling in exchange for trillions of dollars in current and future cuts, Ryan lent his imprimatur to the final deal.

"This bill is far from perfect," he said. "We still have a long way to go toward getting the key drivers of our debt -- especially federal health-care spending -- under control. But considering that House Republicans control only one-half of one-third of the federal government, I support this reasonable, responsible effort to cut government spending, avoid a default, and help create a better environment for job creation."

In the midst of a Republican presidential primary at the time, Mitt Romney struck a different note.

"While I appreciate the extraordinarily difficult situation President Obama's lack of leadership has placed Republican members of Congress in, I personally cannot support this deal," he said.

Also on HuffPost:

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  • Marco Rubio

    "Throughout his life, Mitt Romney has made great decisions, and choosing Paul Ryan as his running mate is a truly inspired choice. I got to know Paul during my Senate campaign when he endorsed me early on when I was still considered a long shot. Paul Ryan is a courageous reformer who understands our nation's challenges, has proposed bold policy solutions to solve them, and has shown the courage to stand up to President Obama and other Washington politicians trying to tear him down. "The Romney-Ryan ticket is going to win in November because it offers the American people visionary leadership to recapture the free enterprise spirit that has empowered countless Americans to build businesses from scratch and live the American dream. I'm excited about the visionary change a Romney-Ryan team will bring to Washington, and I look forward to campaigning

  • Rob Portman

    <blockquote> "Mitt Romney has made a great choice in Paul Ryan. He is an accomplished public servant and a leading voice on the most pressing issues facing our country. Paul is one of my best friends in Congress and someone I have worked closely with as a former colleague on the House Ways & Means Committee. "Jane and I wish Paul and Janna and their kids the very best. As the Chairman of the Romney campaign in Ohio, I look forward to working with Paul to ensure that the Romney-Ryan ticket carries Ohio and is victorious in November. Most importantly, as a member of the Senate, I look forward to working closely with a Romney-Ryan Administration to restore fiscal sanity and enact pro-growth policies to create jobs."</blockquote>

  • Obama for American Campaign Manager Jim Messina

    <blockquote>"In naming Congressman Paul Ryan, Mitt Romney has chosen a leader of the House Republicans who shares his commitment to the flawed theory that new budget-busting tax cuts for the wealthy, while placing greater burdens on the middle class and seniors, will somehow deliver a stronger economy. The architect of the radical Republican House budget, Ryan, like Romney, proposed an additional $250,000 tax cut for millionaires, and deep cuts in education from Head Start to college aid. His plan also would end Medicare as we know it by turning it into a voucher system, shifting thousands of dollars in health care costs to seniors. As a member of Congress, Ryan rubber-stamped the reckless Bush economic policies that exploded our deficit and crashed our economy. Now the Romney-Ryan ticket would take us back by repeating the same, catastrophic mistakes."</blockquote>

  • Michelle Malkin

  • Michael Moore

  • Brad Woodhouse

  • Rachel Maddow MSNBC

  • mike murphy

  • Michael Steele

  • Larry Sabato

  • davidfrum

  • Charles M. Blow

  • Robert Reich

  • Nilay Patel

  • Mark Harris

  • Progressive Change Campaign Committee

    The Progressive Change Campaign Committee issued the following statement: <blockquote>"Paul Ryan is a right-wing extremist who wants to end Medicare. This is a major unforced error by Mitt Romney. It gives President Obama and Democrats a chance to draw a clear contrast in 2012 by promising not to cut one penny from Medicare or Social Security benefits. If Democrats win in a landslide, this was the game changer." -- Adam Green, co-founder, Progressive Change Campaign Committee, a 1 million member grassroots organization</blockquote>

  • Laura Ingraham

  • John Kasich

  • Ari Fleischer

  • Susan B. Anthony List

    The national pro-life organization released the following statement: <blockquote>"By selecting Congressman Ryan as his vice presidential running mate, Governor Romney demonstrates his commitment to protecting American women and unborn children," said Marjorie Dannenfelser, president of SBA List. "A longtime pro-life advocate and a strong fiscal conservative, Congressman Ryan has insisted that there can be no 'truce' when it comes to advancing the rights of the unborn and achieving fiscal responsibility. He has a pristine pro-life voting record and will be an asset to Governor Romney's campaign. "Pro-life voters are a key demographic and help secure victory in critical elections," continued Dannenfelser. "The addition of a second strong pro-life leader to the ticket energizes the pro-life base - we are thrilled with this pick."</blockquote>

  • GOProud

    <blockquote>"The selection of Paul Ryan is a bold and inspired pick," said Jimmy LaSalvia, Executive Director of GOProud. "Paul Ryan has been the architect of policies that would benefit all Americans, especially gay Americans." "Paul Ryan is one of the few political leaders anywhere in the country willing to tell the American people the truth about the unprecedented budget crisis we are facing, and - more importantly - willing to put forward bold plans to put this country back on the road to fiscal solvency," continued LaSalvia.</blockquote>

  • Log Cabin Republicans

    <blockquote>"Congressman Paul Ryan is a strong choice for vice president, and his addition to the GOP ticket will help Republican candidates up and down the ballot," said R. Clarke Cooper, Log Cabin Republicans Executive Director. "As chairman of the House Budget Committee and author of the Republican "path to prosperity" that provided the blueprint for serious spending cuts in this Congress, nobody is more qualified to articulate a conservative economic vision to restore the American economy and stimulate job creation. </blockquote>

  • Sen. John Cornyn (R-Texas)

  • Jason Chaffetz

  • Center For American Progress President Neera Tanden

    <blockquote>"Just like Sen. John McCain's choice of Sarah Palin and George H.W. Bush's selection of Dan Quayle, Mitt Romney has been cowed by the right wing into choosing an extreme vice presidential nominee who will alienate moderate voters. It's now clearer than ever that as president, Mitt Romney would end Medicare as we know it, and will raise taxes on middle class families by more than $2,000in order to slash taxes on the wealthiest Americans. While there is a lot that can be said about Paul Ryan's extreme views, more important is what this choice says about Mitt Romney: that he is unwilling or unable to stand up to the far-right of his party and select a vice-presidential candidate that is both able to be president on day one and capable of governing by reaching across the aisle."</blockquote>

  • SEIU President Mary Kay Henry

    <blockquote>"If there were ever any doubt that Mitt Romney is not on the side of working people, today's choice of Rep. Paul Ryan as a running mate makes it crystal clear. With this choice, Romney has shown the American people that he believes Rep. Ryan's extremist, irresponsible and anti-worker agenda is what's right for our country. "Rep. Ryan has made a name for himself by fighting in the halls of Congress for tax giveaways for the wealthy and big corporations while proposing to gut vital services like Medicare and education, and eliminating any sense of retirement security for working families. His no-holds barred record of attacking seniors, children, and working men and women is frightening for the 99 percent of Americans who are not rich -- but for Mitt Romney it was a calling card to choose him as a running mate."

  • NARAL Pro-Choice America President Nancy Keenan

    <blockquote>"Mitt Romney's choice of Rep. Ryan as his running mate reminds us of why elections matter when it comes to our ability to make personal and private medical decisions," Keenan continued. "The outcome of the 2012 presidential election very well could determine whether abortion remains legal and accessible for the next generation of American women. Romney has pledged that taking away women's rights will be a priority for him and his choice of Ryan amplifies that promise to the extreme anti-choice backers of this ticket. My organization's priority is to make sure President Obama remains in the White House."</blockquote>

  • Kelly Ayotte

  • Herman Cain

  • Rick Perry

  • Tommy Thompson

  • Pete Hoekstra

  • Steve King

  • Eric Cantor

  • Dana Rohrabacher

  • Kenny Marchant

  • Gregg Harper

  • Rick Santorum

  • Rep. Kathy Hochul

    <blockquote>"Americans deserve new ideas for how we can reduce the debt and protect our seniors and the middle class. Just one year ago, Western New York voters rejected the Ryan-Collins policies that would end Medicare as we know it and hurt middle class families while giving more tax cuts to the rich. Our country needs to move forward, not re-hash failed ideas. Given Chris Collins' ongoing support for tax cuts for the rich that add nearly $1 trillion to the deficit and his willingness to send his business to China to line his pockets, it is clear my opponent is going to continue to pursue policies and priorities that have already been rejected."</blockquote>

  • Sen. Lisa Murkowski

  • Claire McCaskill

  • Jim DeMint

  • Chris Van Hollen

  • Rep. Mary Bono Mack

  • Sam Brownback

  • John Shimkus

  • Rep. Trent Franks

  • Frank Pallone

  • Michele Bachmann

  • Rob Zerban

    <blockquote>"Now that Paul Ryan's personal ambition has clearly trumped his interest in the First District, I have no doubt he'll find himself out of a job come November. Once Wisconsinites and voters across our country learn the truth about Ryan's radical plot to end Medicare as we know it, de-fund women's health care, and preserve tax breaks for millionaires, they'll vote against him not just once, but twice. In the coming weeks, our campaign will work with President Barack Obama and Vice President Joe Biden to continue getting the word out on Ryan's indefensible record, and building momentum to ensure victory on Election Day."</blockquote>

  • Scott Walker

    <blockquote>"Governor Mitt Romney made a bold and reform-minded selection in Congressman Paul Ryan of Wisconsin. This election has to be about who is going to look out for the next generation. America needs a comeback team to turn around the economy and to turn around the fiscal status of our country. Romney and Ryan have the ideas and the experience needed to take on these core issues. This is a great day for Wisconsin and an even greater day for America."</blockquote>