Factbox: Scenarios for immigration legislation

WASHINGTON (Reuters) - The debate over how best to fix U.S. immigration laws has been raging for months in Washington after President Barack Obama made the issue a 2013 legislative priority.

Prospects of a bill being enacted this year also got a boost when Republican Party leaders looked at the results of last November's elections and saw that their failed presidential candidate, Mitt Romney, won less than 30 percent of the Hispanic-American vote.

Embracing comprehensive immigration reform would give more Hispanics reason to at least consider Republican candidates, the Republican National Committee concluded.

Despite all this, House Speaker John Boehner has said a comprehensive immigration measure passed by the Senate Thursday will not be considered in the Republican-dominated House.

Still, things could change. Here are some scenarios laying out what could happen next in the immigration debate:

THE CONFERENCE ROUTE

* The wide-ranging bill that passed the Democratic-held Senate on Thursday, by a 62-38 vote, gets temporarily set aside by the Republican-controlled House of Representatives.

* This summer or fall, the House debates one or more narrow immigration bills. The most likely would be one that tries to stop all illegal immigration over the U.S. border with Mexico.

Other possibilities are a bill that provides more visas for foreign high-tech workers or one that helps American farmers get more cheap labor from abroad. None of these bills puts 11 million illegal immigrants on a pathway to citizenship, as the Senate bill does.

* Once the Senate and House have passed their respective bills, the two chambers appoint negotiators to work out a compromise - one bill that could pass both houses. The negotiators are called conferees and they meet in conference to hammer out a deal.

* The deal they work out is sent to the House and Senate where each chamber votes to pass the same bill that then would go to Obama for signing into law.

* The danger - one that Republican and Democratic aides say is likely - is that the conference deadlocks over the pathway to citizenship and the whole process collapses.

THE PING PONG ROUTE

* The House simply takes up the Senate-passed bill. Boehner already has ruled out this possibility because the majority of his Republicans oppose the Senate bill.

But some Democrats still harbor hopes that so much pressure will be thrust on the House in coming weeks and months to pass a comprehensive bill, one with the pathway to citizenship, that it will be forced to act on the Senate bill.

Obama no doubt will try to whip up support, as will immigration advocacy groups who are planning high-profile demonstrations and other lobbying efforts.

* The House relents and takes up the Senate bill.

* But it likely would amend it and send it back to the Senate to pass in its latest form.

* This process could continue with different versions flying back and forth between the House and Senate, like a ping pong game.

* Again, the danger is that each side ultimately sticks to its guns and the whole process collapses.

* Conversely, at some point, Boehner tells his rank and file that he has done all he can do to moderate the Senate bill and for the good of the party and the country, it is time to cut a deal. Some Congress-watchers say this is dangerous territory for Boehner. He could end up backing an historic bill that passes with the support of most Democrats and only a minority of Republicans. And that, some speculate, could put Boehner's job in jeopardy.

THE FASTEST DEAD-END ROUTE

* The Senate passes a bill.

* The House passes a much different bill or does nothing.

* Everybody agrees the two sides cannot work out a compromise and each side blames the other for failure.

* Immigration becomes nothing more than a political fundraising tool in the run-up to the 2014 congressional elections and 2016 presidential elections.

This already has begun.

Republican Representative Steve King, a Tea Party favorite from Iowa, made a fundraising appeal on Thursday in which he tried to cash in on his opposition to the Senate bill.

Calling the proposed pathway to citizenship "amnesty," King wrote, "Show the Senate, House leaders, and amnesty activists we won't stand for it by helping me raise $50,000 by midnight on June 30."

THE 2014 ELECTION ROUTE

Democratic strategist are looking ahead to the 2014 congressional election as a possible fall-back position.

If House Republicans refuse to pass comprehensive immigration reform, Democrats could run on the issue next year.

Democrats would target Hispanic and young voters to drum up support, possibly winning back control of the House.

"We could then pass immigration reform in 2015," said a senior Democrat aide.

(Additional reporting by Thomas Ferraro; Editing by Fred Barbash, Mary Milliken and Bill Trott)