"This is a survival of the fittest moment," observed Michael Franc, vice president of government relations for the conservative Heritage Foundation.
Franc said that immigration, joined with federal spending and the war in Iraq, will be the pre-eminent issues in the midterm election for right-of-center voters, who are "seeing the world through the prism of immigration reform right now."
Unlike their Senate counterparts, House Republican leaders have been loath to get behind the president in his call to enact legislation that would create a temporary worker program open to those who have illegally entered the country.
One senior House GOP leadership aide argued that any attempt to put their members on record before the midterm elections will "annihilate" their conservative base, which considers any form of temporary worker program as synonymous with amnesty.
When asked Tuesday to respond directly to Bush's support of providing illegal immigrants with a path to legal status, House Speaker Dennis Hastert, R-Ill., only reiterated his support for border security legislation.
"I think the president reflected a lot of the ideas we have in Congress," Hastert said. "The first thing we have to do is enforce the border, and then we can look at alternatives."
House Majority Whip Roy Blunt, R-Mo., has been equally reluctant.
"While I appreciate the president's willingness to tackle big problems, I have real concerns about moving forward with a guestworker program or a plan to address those currently in the United States illegally until we have adequately addressed our serious border security problems," he said Monday.
House Majority Leader John Boehner, R-Ohio, has declined to offer his personal view of a guest worker program.
"I am the leader of House Republicans, and as a leader you have got to take your own personal position on some issues and set it aside and look at where the team is going," he said Tuesday.
House GOP leaders say they stand behind their border legislation because polling indicates it is a popular first step, with less potential fallout.
"If you look at all the polling, they are very supportive of what the House did, in terms of enforcing the borders and enforcing our laws," Boehner said.
"Border security is one of the few things that are working for them right now and they don't want to give that up lightly," noted Franc.
But the Senate bill on the floor this week includes a temporary guestworker proposal -- and Senate Majority Leader Bill Frist, R-Tenn., said Tuesday he scheduled two weeks of open debate in hopes of convincing Americans that the country needs a comprehensive approach. "The American people will understand it's much more than just building a fence," said Frist. Not all of his colleagues are convinced.
"They're playing a high-wire act," said Sen. Jeff Sessions, R-Ala., about Senate GOP leaders and the president.
Sessions agrees with the House position and has urged Senate GOP leaders to enact border security legislation this year and then hold hearings on the economic effects of a guestworker program before passing a proposal.
But several Republicans worry that if they do not pass a House-Senate compromise before the election, voters could see the GOP-controlled Congress as lacking leadership on a defining issue.
"[Former Senate Minority Leader] Daschle lost and Democrats got bumped down because of the 'obstructionist' label," Sen. Norm Coleman, R-Minn., said Tuesday about the 2004 election cycle when Republicans accused Democrats of blocking their efforts to enact legislation. "And we could fall victim to the same fate if we're not careful."
Franc noted that Republicans also need to mind three main constituencies in this debate: their core party constituency, the business community, and Hispanic voters.
"The worst-case scenario is you find a way to anger them all -- which is doable," he said.
Sen. Sam Brownback, R-Kan. -- a potential presidential candidate in 2008 who supports a comprehensive approach -- said Tuesday that the initiatives Bush announced Monday night could be enough to provide political shelter for the party if GOP leaders fail to push through a comprehensive bill this year.
Republicans believe that for the two chambers to reach middle ground, the president needs to play a critical role. Despite Bush's low approval numbers, Sen. Lindsey Graham, R-S.C., said the president, "on this issue, has unique sway."
While several Republicans said Bush's speech helped build momentum for a comprehensive bill, one GOP aide said it also painted GOP lawmakers into a corner. If Congress decides not to pass an immigration bill this year, it will be viewed as a rebuke of the president. "That's the danger in the president giving a speech like that," said the aide.
The White House acknowledged that they will need to be diligent in negotiations with Congress.
"I can't tell you exactly how we're going to deal with Roy Blunt or Denny Hastert or anybody else. But I guarantee you the president knows that this is an issue of sufficient concern that he is going to pay heed to friends and allies on Capitol Hill," White House Press Secretary Tony Snow said Tuesday.
White House Deputy Chief of Staff Karl Rove will be at the weekly House GOP Conference meeting Wednesday to talk about immigration.
With Bush's approval ratings at historic lows, however, some argue that the White House will not be able to drive this debate, particularly as leaders in both chambers are cognizant of the party's vulnerability of losing seats -- and possibly the majority -- come November.
"This is where your presidential moment comes in," Franc said. "If [Bush] in good faith realizes that the House can only go 10 percent of the way he'll have to ask himself, 'Can I settle for a partial solution now and make a stronger case in the next Congress?' To do it all in one fell swoop, if that's his decision, he's probably not going to get very far."