During the 2012 presidential election, Republicans didn’t consider income inequality a problem, and no one expressed that opinion better than their candidate, Mitt Romney. “You know, I think it's about envy,” he said in January 2012. “I think it's about class warfare.” Instead, Romney focused on opportunity. “I believe in a merit nation, an opportunity nation where people by virtue of their education, their hard work and risk taking and their dreams—maybe a little luck—could achieve great things,” he added.

On CBS’s “Face the Nation” Sunday, former Pennsylvania Senator Rick Santorum criticized Romney for that rhetoric. “I think there's also evidence that [Romney] didn't do a very good job reaching out to the very voters that I just talked about,” he said. “I think there's a lot of folks who are very disenchanted with both political parties because neither party is really talking about them and really saying what's the way forward for the 70 percent of Americans who don't have a college degree but, you know, want economic opportunity like everybody else.”

But for all his criticism of Romney, Santorum doesn't sound much different: Both of their comments were clearly focused on mobility and opportunity. And that makes Santorum an outlier in the Republican field, where others have been unafraid to touch a previously toxic issue on the right: income inequality.

“We’re facing right now a divided America when it comes to the economy,” Senator Ted Cruz said on Fox News after President Barack Obama’s State of the Union. “It is true that the top 1 percent are doing great under Barack Obama. Today, the top 1 percent earn a higher share of our national income than any year since 1928.” Senator Rand Paul had a similar reaction to the State of the Union. “Income inequality has worsened under this administration,” he said. “And tonight, President Obama offers more of the same policies—policies that have allowed the poor to get poorer and the rich to get richer.” Even Romney’s rhetoric has changed to show greater concern about inequality.

And yet, many conservative economists side with Santorum in believing that economic mobility is a more dire problem in America than income inequality.