The fate of comprehensive immigration reform hinges in large part on Nov. 2's elections, President Obama said Monday in an appeal to Latino voters.

The president said that he was short on votes to pass immigration reform in Congress, and that major Republican victories on Election Day could further imperil his ability to pass a bill that reforms the immigration system and provides a path to citizenship for illegal immigrants.

"If the Latino community decides to sit out this election, then there will be fewer votes and it will be less likely to get done," Obama said on the "Piolín por la Mañana" program on Univision Radio.

The warning from Obama comes as part of a broader effort by the administration in recent weeks to drive up turnout among voting blocs that are considered typically supportive of Democrats. Obama has made appeals to young and first-time voters from 2008, as well as African-American voters, in order to help House and Senate Democrats stave off the kinds of heavy losses that would hand Congress to Republicans.

Obama said he understood Latinos' frustration that he hadn't been able to follow through on his promise to push for immigration reform. But the president said that since he couldn't even get all Democrats on board, he'd need Republicans help.

"First of all, on immigration reform, I can't get 100 percent of Democrats. I can get 90 percent of Democrats, but I can't get 100 percent," he said. "Right now on immigration reform, we're eight votes short or 10 votes short, so we have do the work behind the scenes to build the groundswell of support that can get us then over the finish line."

"I'm not asking for 100 percent support from Republicans. I'm not asking even for 50 percent support from Republicans," Obama later added. "I just want a little bit of support so that I can actually get this thing passed."

The president pointed to one Republican candidate — Nevada Senate candidate Sharron Angle, who's challenging Senate Majority Leader Harry Reid (D) — as an example of a GOP candidate who, if they win, would make comprehensive immigration reform more difficult. 

Obama's comments could weigh heavily on some races in the closing days of the campaign, motivating Democrats and Latinos to vote, but also Republicans as well. Arizona Gov. Jan Brewer (R) saw a surge in support after she led her state to enact one of the toughest laws against illegal immigrants earlier this year. Other races in the West and Southwest — in states like California, Arizona, Nevada and Colorado — could see immigration become a salient factor in voters' decisions.

Latino voters, the president said, would have an opportunity to send a message to Republicans, who Obama accused of "politicizing" immigration reform and the border security debate. Obama said "pressure has to be put on the Republican Party" if immigration reform is to become a reality.

"And if Latinos sit out the election instead of saying, we're gonna punish our enemies and we're gonna reward our friends who stand with us on issues that are important to us, if they don't see that kind of upsurge in voting in this election, then I think it's gonna be harder — and that's why I think it's so important that people focus on voting on November 2," he said.