President Obama on Tuesday delivered a forceful speech calling on Congress to overhaul the country's immigration system, declaring, "We're finally at a moment when comprehensive immigration reform is within our grasp." Obama's remarks came a day after a bipartisan group of eight senators released the outline of a reform plan, an effort that Obama praised. "For the first time in many years, Republicans and Democrats seem ready to tackle this problem together." 

However, Obama warned that he would take action if Congress failed to act. "If Congress is unable to move forward in a timely fashion, I will send up a bill based on my proposal and insist that they vote on it right away." 

Some commentators have suggested that the main obstacle to reform is Obama himself, because his involvement could alienate Republicans at a time when bipartisan momentum for the bill is building a head of steam. Indeed, Sen. Marco Rubio (R-Fla.), the GOP's point man on the Senate plan, earlier in the day won heaps of praise for his efforts from none other than Rush Limbaugh, an indication of how effectively Rubio has sold the bill to staunch right-wingers.

In that respect, immigration reform may be better off if Obama simply allowed Rubio and the Group of Eight to build congressional support for the legislation. Obama's own proposal is virtually identical to the bipartisan outline, featuring four central elements: Beefing up border security; cracking down on companies that hire undocumented workers; requiring those seeking citizenship to pay taxes and a penalty; and streamlining the immigration system — all with the goal of offering a path to citizenship for the country's 11 million undocumented workers.

There are, however, two areas upon which Obama and the GOP disagree. Obama wants same-sex couples to be treated the same as straight couples under the new immigration system, which many Republicans consider a poison pill that could kill the legislation. "Why don't we just throw taxpayer-funded abortion in there?" said a frustrated Sen. Lindsay Graham (R-S.C.). However, Obama notably did not mention same-sex couples in his speech, an indication that the administration is not inflexible on the issue.

The GOP has also demanded, at least so far, that the legislation include a "trigger mechanism" that would make reform dependent on strengthening border security first. Conservatives argue that the administration could easily skirt the border-security provisions unless a trigger mechanism is in place. Analysts expect the trigger to become a focal point of the debate as it moves forward.

Overall, Obama's speech did not seem to contain anything that would scuttle support for the bill. At this point, the heaviest lifting will fall on national GOP leaders concerned about the the party's estrangement from Latino voters. For Rubio and other Republicans in the Group of Eight, the next challenge will be convincing conservative representatives in the House to go along. And that's where serious opposition could emerge to the party's remarkable, 180-degree turnaround on the issue.