MADISON, Wis. -- The civil unrest that filled the streets of Wisconsin's Capitol Square two years ago has long since dissipated. The roads are quieter, no longer littered with signs and bumper stickers and angry petitioners trying to oust the governor. Midwest manners have returned to once bitterly divided neighborhoods.

The furor over Gov. Scott Walker's decision to curb the collective bargaining powers of most public employee unions culminated in 2011 in a massive, extended protest by workers and their allies, the spectacle of Democratic lawmakers fleeing the Capitol to prevent the proposal's passage and a recall election that ultimately failed to force Walker from office. But it also shifted the national spotlight onto a Republican governor who until then was virtually unknown outside his state, propelling Walker to political stardom and a potential run for the GOP presidential nomination in 2016.

As Wisconsin's fervor faded over the past two years, however, so has the attention paid to Walker. Press attention has shifted to the likes of New Jersey Gov. Chris Christie, who is far better known nationally than Walker, and Sens. Marco Rubio, of Florida, Rand Paul of Kentucky, and Ted Cruz of Texas, all of whom get far more notice from Beltway insiders than the governor of Wisconsin.

Yet there is little doubt in Wisconsin that Walker harbors hopes of taking a run at the presidency in 2016. It's the one thing the state's Democrats and Republicans have agreed on since the former Milwaukee County executive became governor in 2011.

Walker is doing everything potential presidential contenders do to test the waters more than two years out from Election Day. He has spent time in the crucial early battlegrounds -- New Hampshire and especially neighboring Iowa -- and visited a dozen other states: Alabama, Arizona, California, Colorado, Connecticut, Florida, Illinois, Kentucky, Nevada, New York, Texas and Tennessee. Sometimes he travels to raise money; other times he's cashing in political IOUs; on other occasions he goes because states want to hear how he took on Wisconsin's public employee unions.

He also has a well-timed, profile-raising book coming out this fall, "Unintimidated: A Governor's Story and a Nation's Challenge," which, according to those familiar with it, might as well come with a "Walker for America" bumper sticker.

The governor was one of the leading Republican critics of Mitt Romney, the party's 2012 presidential nominee, a candidate many conservatives never wanted. And at last year's Republican National Convention, Walker's ovation upstaged Romney.

When asked whether these are signs that he'll run, Walker, in accordance with the traditional presidential candidate script, demurs. "We'll take a look at it," he said earlier this year when asked about plans for 2016.

Walker is far from a household name, but within GOP circles he is taken seriously as a dark-horse candidate.

His resume reads like a conservative punch list, and his fierce, first-term war against labor unions inspired GOP leaders across the country to attempt the same. Walker has expanded a school voucher program across most of the state, cut income taxes across the board and signed a pro-life measure requiring women to undergo an ultrasound examination before getting an abortion.

It also doesn't hurt that he lives next door to Iowa, where the first-in-the-nation caucuses can bestow credibility on a long-shot candidate, and is close to Republican Gov. Terry Branstad, a potentially critical ally.

"He has a lot of respect and admiration on this side of the Wisconsin border," said Bob Vander Plaats, president and CEO of the Family Leader, a socially conservative organization in Iowa where Plaats is a GOP kingmaker. "They've appreciated his boldness in taking on the unions and providing some real leadership. He would have a very fair playing field here and a lot of people willing to welcome him."

National Republicans see Walker as battle tested. His fight to retain office in a recall election barely a year into his first term introduced him to national GOP donors -- including billionaire brothers David and Charles Koch -- who helped him amass a state-record $30 million war chest. That race also helped lionize Walker in conservative circles as the Republican who pushed back in a state with a rich progressive history and a penchant for voting Democratic in presidential elections.

At home, however, Republicans are less enthusiastic about Walker's national ambitions, wishing he'd focus more on his 2014 re-election campaign, which is far from a slam dunk. Walker's approval rating stood at 48 percent in a recent Marquette Law School poll, and his disapproval numbers hit 46 percent, a testament to just how polarizing Walker remains.

"The question for him is when he moves out of the state, are there any areas where he would take positions that would reduce that polarization," said Marquette Poll Director Charles Franklin. "He stayed very close to the more conservative wing of the party in his governing here."

Democrats, who are virtually powerless in Madison, have reason enough to want to recapture the governor's office after two years of being steamrolled by a Republican majority. But blocking Walker's path to the White House is an added incentive.

"I think he's going to run [for president] even if he lost [the governor's race]," said Mike Tate, chairman of the state Democratic Party. "He'll paint himself as a martyr. But I think it takes him off the board as a serious contender."

Walker refused numerous Washington Examiner requests for an interview. A close ally, Milwaukee conservative talk show host Charlie Sykes, said Walker doesn't want to get caught up in speculation about his chances.

"I've grown up with Scott. I've known him since before he was in the Assembly," Sykes said. "The one thing about Scott Walker is at every stage of his career, his opponents and even some of his friends underestimate him. He understands and relishes that people often don't see him coming or they peg him in a certain way."

In addition to facing almost certain, well-funded opposition from labor unions, Walker would have to explain to a national audience why he failed to create the 250,000 new jobs he promised in his gubernatorial campaign, a goal now virtually impossible to reach by Election Day. Democrats are quick to note, too, that Wisconsin's job growth actually declined under Walker, falling from 11th nationally to 38th, according to the Bureau of Labor Statistics. The Federal Reserve Bank of Philadelphia ranks Wisconsin 49th in economic outlook.

"He'll have some strong punch lines when you have a Republican debate but there's not that much else for the rest of the population to really rally around," said state Senate Minority Leader Chris Larson. "They're not long-termed, long-visioned policies. They're very sugar-high punches."

Sykes said a candidate like Texas Gov. Rick Perry could trump Walker on economic growth. "Let's face it: [Running for president] would be a huge leap for Gov. Walker," he said.

Walker may appeal to Republicans eager to win his traditionally Democratic state, but the governor isn't the most popular 2016 contender among Wisconsinites, who favor Rep. Paul Ryan, last year's vice presidential nominee, a Marquette poll showed. Walker wasn't even runner-up. He placed third behind Florida's Rubio.

"The governor and Congressman Ryan have had a good relationship to the point where they are both seen as likely presidential contenders," one Republican lawmaker said. "Yet, I think it's unlikely that you'll see both of them run."

One Republican close to Walker said many in the party fret that he could be haunted on a national campaign trail by his failure to finish college. But others said Walker's mastery of retail politics will blunt voter worries and boost his chances in New Hampshire and Iowa. While running for governor, Walker rode his Harley across the state, wore a Green Bay Packers jersey, tailgated at Lambeau Field and held brown-bag lunches in offices across Wisconsin. Those who have watched his political career say he has only gotten stronger on the stump.

Former New Hampshire Republican Party Chairman Wayne MacDonald said Walker wowed the rank and file at the state party convention last year.

"I remember introducing him and the crowd went absolutely wild. I've never heard a louder crowd at a convention," MacDonald said. "He was down to earth, he was conversational, he was unassuming."

Walker remains largely unknown to most Republicans in New Hampshire, the nation's earliest primary state, despite his travels there, MacDonald said. But a successful re-election bid in 2014 would boost his stature.

"A lot rides on his own re-election," MacDonald said. "But he's been such a good Republican on the issues that drive Democrats crazy. He's an exciting talented candidate that has a lot to offer."