There’s a brewing debate in Washington over the proposed immigration overhaul. Or more accurately, there’s a brewing debate about the debate.

Should Congress and President Barack Obama move quickly while the politics favors comprehensive legislation, including the legalization of the millions of illegal immigrants currently residing in the United States? Obama and the Democrats would move fast if they had their druthers, and in fact, they are being pushed to do so by left-wing advocates of immigration reform.

Or should lawmakers embrace the deliberate, methodical and, yes, slow approach advocated by Sen. Marco Rubio, R-Fla., and House Judiciary Chairman Robert W. Goodlatte, R-Va? The senator and the congressman have continue to press their argument — that a swift debate would scare bedrock conservatives and other Republicans who are supportive of overhauling immigration but sensitive to any political backlash from the GOP base, leading to its defeat.

The risk to going slow is that it provides opponents the time they need to marshal resources and produce academic research undermining the case for rewriting U.S. immigration law, not to mention time to apply political pressure to supporters and possible supporters, of the effort. Such action is already under way on several fronts. But in this case, the benefits to moving deliberately outweigh the risks — by far, particularly in a post-“Obamacare” environment.

Even before either of the House or Senate bipartisan working groups have introduced their legislative proposals, the Republicans in each gang are taking a barrage of daily hits from other Republicans either suspicious of their efforts or downright opposed to any bill that would provide legal status to illegal immigrant residents.

Thus far, most Republicans have maintained a wait-and-see attitude, in large part due to the lobbying of Rubio and House conservatives such as Raúl R. Labrador of Idaho and Trey Gowdy of South Carolina. But Senate Budget ranking member Jeff Sessions, R-Ala., on Tuesday sent out yet another attack in the form of a press release suggesting no amendments will be allowed should the Senate “gang of eight’s” bill ever reach the floor.

If you don’t check your email by the hour, you might miss another attack, and a knowledgeable source monitoring the immigration overhaul push told me Monday that Republican Senators in particular are getting “twitchy.” This source said even Republicans who favor a comprehensive immigration rewrite fear that, like the Affordable Care Act, the legislative process will proceed faster than is required to fully digest what’s in the bill, leading to painful political surprises later.

Forget for a moment that Rubio and other conservatives are walking a fine tightrope as they seek to implement a comprehensive immigration overhaul that addresses illegal immigrant residents and might have selfish political motivations for advocating a slow approach with countless hearings, robust committee markups and an open floor process.

If the proponents of this latest effort want it to fare better than the failed 2007 attempt to overhaul immigration; if they want the prevent the debate from devolving into the political mess that became the Affordable Care Act and left that landmark law as unpopular now as it was three years after Obama signed it, then take it slow. “Never again can Congress pass a far-reaching proposal only for the American people to find out what’s in it later,” Sessions said in his latest email blast.

At least say you’re willing to take it slow if that’s what members claim they need to get comfortable with the legislation.