Wisconsin Gov. Scott Walker (R), who could run for president in 2016, says the problem with Mitt Romney's 2012 presidential campaign was that Romney did not make a strong enough positive case for himself. 

"They took the best things about Mitt Romney and hid them," Walker said in an interview with GQ published Tuesday. "And they made the huge mistake of thinking that the 1980 Reagan campaign was based on the premise of that great question, 'Are you better off than you were four years ago?'" 

Walker said that should have just been the closing argument.

"Often as Republicans we tend to do this — we get what's wrong about Barack ObamaBarack Hussein ObamaAnother chance to seek the return of fiscal sanity to the halls of Congress Colombia’s new leader has a tough road ahead, and Obama holdovers aren't helping An alternative to Trump's family separation policy MORE," he said. "And Americans know it, too; you didn't need to beat it in. You needed to show how you'd be different."

He said he emailed the campaign advice in 2012, but after a particularly pointed email arguing Romney needed to be positive, he never heard back. 

Walker gained a national profile through his battles with public sector unions in the state. But, if he himself wants to run for the Oval Office, he first has to get through a reelection battle this year with Democratic businesswoman Mary Burke.

A federal judge last week lifted a hold on the investigation into possible campaign finance violations by Walker's campaigns in 2010 and 2012. 

"It's my plan, if the voters will have me, to be governor for the next four years," Walker said on Monday, but that does not necessarily mean the plan could not change down the line. 

In the GQ interview, Walker emphasized the need for Republicans to be positive. 

"One of the problems I see with Republicans nationally — well, three," Walker said. "They're always against Obama, so they're not optimistic. I try to be optimistic and visionary. Second, they talk in terms that most people can't relate to. Fiscal cliffs and sequesters don't mean anything to most people. I talk about whether your kid coming out of college is gonna have a job. And third, they don't get out much — and I'm around the state quite a bit."

"Not that any Republican is necessarily going to win the majority among women, younger voters or ethnic minorities," he said at another point in the interview. "But we can do a lot better. I go to places where you'd never dream of seeing Mitt Romney or John McCainJohn Sidney McCainOvernight Defense: States pull National Guard troops over family separation policy | Senators question pick for Afghan commander | US leaves UN Human Rights Council 13 GOP senators ask administration to pause separation of immigrant families McCain, Coons: Trump should withdraw controversial refugee nominee MORE."