With a comprehensive overhaul of the immigration system dead, Democrats and immigrant advocates believe the Dream Act is the last best chance to win legal status for at least some illegal migrants before Republicans take control of the House in January.

Republican leaders said the bill is just another form of "amnesty", one that is too costly to taxpayers and will only invite more illegal border crossings.

The Senate is scheduled to vote on the bi-partisan legislation, which would potentially legalize hundreds of thousands of young people, on Thursday. Sen. Harry Reid (D-Nevada), majority leader, is not expected to have the 60 votes needed for passage.

In a last-ditch showdown on immigration relief for illegal migrants, the Democratically-controlled House of Representatives on Wednesday narrowly approved the so-called Dream Act that would offer a pathway to citizenship for undocumented young people who attend college or serve in the military.

Democratic congressional leaders chose to push forward with the Dream Act, a bipartisan bill, because even some conservatives believe that the young people who would benefit were brought here illegally by others through no fault of their own and should not have to suffer for it.

The Obama administration has supported the Democrats’ effort and, in a statement on Wednesday, repeated its strong endorsement. “While the broader immigration debate continues, the administration urges the Senate to take this important step and pass the Dream Act,” it said.

In addition, the measure is supported by some pro-military groups as a way to help provide for the nation’s military needs. Clifford Stanley, the undersecretary of defense for personnel and readiness, said this week that the measure was a “common-sense" and "obvious" way to attract more high-quality recruits to the armed forces.

Faith groups and many educational leaders also mobilized for the measure, including UCLA Chancellor Gene Block, who argued that the students’ skills and talents were badly needed to help the nation in an increasingly competitive global economy.

The legislation would give hundreds of thousands of illegal immigrants a chance at becoming legal. The requirements state that, to be eligible, a person must have been brought to the United States before he or she was 16, been in the United States for five years, earned a high-school degree and be attending college or be in the military.

In recent days, Democrats had aimed to pick up some Republican support by dropping the maximum eligible age from 35 to 29, extending the waiting period for a green card from six to 10 years and eliminating the requirement that Dream Act youth pay tuition at in-state rates rather than out-of-state rates. In-state tuition, which is what undocumented students in California pay, amounts to an average annual public subsidy of about $6,000 nationally per student.

Some Democrats, in an effort to attract Republicans in agricultural states, had also pushed to add to the Dream Act provisions to ease the process to bring in legal farm workers.

Most Republicans opposed the act as unjustified “amnesty” for lawbreakers or said no legalization should be considered until the border was first secured. Others said they would be willing to consider legal status for the youth but opposed provisions to allow eventual legalization of their lawbreaking parents. Still others objected to the added cost for public services for the Dream Act youth.

A Congressional Budget Office analysis this month estimated the House version of the Dream Act would reduce deficits by about $2.2 billion and increase revenues by $1.7 billion over the 2011-2020 period. It estimates that the Senate version of the legislation would reduce deficits by about $1.4 billion and increase revenue by $2.3 billion over the 2011-2020 period.

The Dream Act “rewards parents who broke the law through their kids, puts a significant expense on taxpayers and will overwhelm community colleges with new students,” said Ira Mehlman of the Federation for American Immigration Reform.

Ivan Rosales, a 21-year-old senior and biology major at Cal State San Bernardino, said he has dreamed of becoming a military doctor. Rosales, who was brought here illegally by parents from Mexico when he was less than a year old, was a straight-A student at Rialto High School and a science whiz awarded science fair honors and a merit-based presidential scholarship.

He was attracted to the military after joining the ROTC high school program and finding he enjoyed the discipline and organization, he said. He also was inspired by an older brother in the Air Force Reserves and a brother-in-law who served in Iraq. But unless he has legal status, he cannot join the military.

“Being in the military is the ultimate sign of your patriotism and showing your love for this country and its values,” Rosales said.

If the bill fails in the Senate, immigrant advocates say they won’t give up. In coming months, advocates say, they will assess their options -- including ways to leverage the growing number of Latino voters as national elections loom in two years.

“There’s going to be a lot of heartbreak and blame-placing, but we will have to regroup,” said Antonio Gonzales of the William C. Velasquez Institute, a Los Angeles-based public policy analysis group.

RELATED:

UCLA Chancellor Gene Block urges passage of Dream Act

Should illegal-immigrant college students have path to citizenship?

Fresno State student body president acknowledges he is an illegal immigrant

-- Teresa Watanabe