Lawmakers on Capitol Hill piled on the criticism of Jeb Bush Tuesday after the former Florida Republican governor seemed to change his position on whether illegal immigrants should be offered a "path to citizenship" as part of an immigration reform package.

Bush's promotional tour for his new book, "Immigration Wars," hit a snag when he told the "Today" show Monday that illegal immigrants currently living in the U.S. should return home before being allowed to apply for citizenship. Bush walked the comments back on Tuesday, saying he would support a path to citizenship if it didn't incentivize more illegal immigration.

With Congress still in the early stages of crafting a comprehensive and fragile immigration reform bill, House Majority Leader Harry Reid slammed Bush, and downplayed Bush's role in the national debate over the issue.

"His opinion on immigration is not evolving, it's devolving. He keeps going backwards," Reid said Tuesday when asked about Bush's comments. "I think he's frankly made a fool of himself the last 24 hours. Frankly on this issue, I don't think Jeb Bush is a Florida leader. I think Marco Rubio is. Bush has been elected to nothing lately. Rubio is the leader on immigration. He wants to have an immigration bill; I appreciate that."

Bush's comments appear to be a reversal from June 2012, when he said he "would support" a "path to citizenship" for illegal immigrants.

Because immigration reform relies on a delicate framework of liberal and conservative coalitions, there is a fear on Capitol Hill that any outside comments from influential lawmakers—both former and current—could derail the effort.

And that fear is bipartisan.

"This proposal caught me off guard," South Carolina Sen. Lindsey Graham, one of the lead Republicans on immigration reform, said Tuesday of Bush's comment. "It undercuts what we're trying to do."

Bush is scheduled to meet with political reporters in Washington, D.C., Thursday, after participating in a forum on immigration reform at the Cato Institute, a libertarian think tank.