The odds of passage for comprehensive immigration reform are looking bleaker. What options do supporters still have?

The reluctant cooperation on immigration reform exhibited by many Republicans after last year's presidential election has evaporated, particularly in the House of Representatives. On Friday, the Republican National Committee, called for immigration reform, but firmly opposed a path to citizenship for any of the 11 million undocumented immigrants in the country.

That position runs completely counter to the proposal outlined in the bipartisan Senate bill passed earlier this year. House Republicans instead are calling for a piecemeal approach, a plan President Obama and Democrats have flatly refused, since they would have no way to guarantee that agreeing to initial Republican demands would lead to legalization en masse.

The impasse continues to grow. On Sunday, House Rep. Bob Goodlatte, one of the main opponents of immigration reform, told Face the Nation that he has concerns over border security, despite the fact that the Senate bill allots billions of dollars to border control.

"First you have to assure there's not going to be another wave of illegal immigration," Goodlatte said. "We have to again, restore the trust of American people by saying that the law is going to be enforced. We need new laws on employment verification, on entry exit visas system, on allowing state and local law enforcement to have a clear statutorily defined role."

Democrats contend that all those concerns have been addressed by the Senate bill. Indeed, half of the "Gang of Eight" that authored the bill is Republican.

Reform proponents are getting tired of Republican intransigence and stalling, and are seeking ways around the conservative blockade. Some analysts think they may resort to an old legislative trick, a discharge petition.

The petition would allow House Democrats to circumvent Speaker John Boehner, who refuses to bring any legislation, including immigration reform, to the floor of the House unless it has the support of the majority of Republicans, an unlikely scenario for immigration reform.

But a discharge petition could conceivably allow passage of an immigration bill with a simple majority if the House, achievable with the support of only some Republicans, as long as nearly all Democrats are on board.

That's a possibility, but it's also a last resort, and Democrats are hesitant to use the tactic until all other options run out. But with such a broad coalition of support and so many people depending on immigration reform, they may have no choice.