House proponents of comprehensive immigration reform unveiled their mammoth proposal Tuesday, with hopes that President Barack Obama will give a new push to their cause early next year.

The 700-page measure has 88 Democratic co-sponsors from a mix of liberal caucuses and ties together a mix of contentious provisions, namely a pathway to legalization for illegal immigrants. Rep. Luis Gutierrez (D-Ill.), who has been leading the charge for immigration reform in the House, said Tuesday he is handing off ownership of the bill to Rep. Solomon Ortiz (D-Texas) since he founded the Congressional Hispanic Caucus and is the longest-serving Member of the group.

Bill supporters say they are optimistic that they will find the 218 votes to pass the bill by spring, despite its current lack of support among Republicans and moderate Democrats. “We’re getting the confidence from the mosaic you see here this afternoon,— said Gutierrez, referring to the racial and ethnic diversity of lawmakers co-sponsoring the legislation.

In addition, Speaker Nancy Pelosi (D-Calif.) is “a wonderful, consistent ally— who walks with “a new step when she talks about immigration, a new energy, a new vigor. … She seems awfully optimistic … in all of her body language to us,— said Gutierrez.

But Gutierrez hasn’t given the same glowing praise to Obama, who has vowed to advance the issue next year but dealt a blow to the cause this fall when he pushed for restrictive language on illegal immigrants in the Senate health care reform bill.

Congressional Hispanic Caucus Chairwoman Nydia Velázquez (D-N.Y.) defended the president’s actions.

“This is comprehensive immigration reform. We are not going to take other legislative vehicles … to address immigration,— Velázquez said. “President Barack Obama consistently has said that he is going to lead the way for comprehensive immigration reform. I believe that President Barack Obama is a man of his word and I take him at his word, unless I hear differently.—

Velázquez emphasized that Hispanics came out in full force to elect Obama last November because they had “one thing in mind: comprehensive immigration reform. So today, at the end of 2009, we are laying down a marker to say unequivocally that 2010 will be the year when our nation finally addresses immigration.—

Advocates of a comprehensive overhaul concede that they have a very small window to pass their measure before it gets too close to midterm elections. Gutierrez has said that April 1 is the target date for passing a bill; beyond that, he has said, it becomes increasingly difficult.

Regardless of the timeline, Gutierrez said to expect critics to use their bill as a wedge issue in the buildup to elections. “The immigrant blame game is one of the most predictable, most deplorable elements of public debate in our nation,— he said.

House Republicans were already lining up to criticize the proposal.

Rep. Jeff Flake (R-Ariz.), who co-sponsored immigration reform legislation with Gutierrez in 2007, blasted the bill for not including a temporary worker program and for watering down penalties for illegal immigrants applying for legal status.

“I’m still hopeful that Congress will address immigration reform soon. States like Arizona desperately need it. However, it will need to be more comprehensive than the Gutierrez bill in order to be effective,— Flake said in a statement.

Judiciary ranking member Lamar Smith (R-Texas) said the bill is already dead on arrival since “the American people oppose rewarding lawbreakers, which then encourages even more illegal immigration.— Similarly, Republican Study Committee Chairman Tom Price (Ga.) said Republicans are willing to debate the issue if lawmakers “once and for all put to bed the amnesty-first approach to immigration reform.—