WASHINGTON Immigration isn't a touchy subject just for many Republicans. Southern and moderate Democrats also may be a bit skittish about the idea of granting a path to citizenship for the nation's 11 million illegal immigrants.
A small group of Senate Democrats, because they represent conservative states such as North Carolina and Arkansas, could help derail ambitious plans to overhaul the nation's immigration laws.
Views on illegal immigration are very different in the conservative South, where moderate Democrats have long sought to strike a balance between a range of issues on their party's agenda and the divergent opinions of those who elect them.
President Barack Obama won the presidency in part because of Latino support in the swing states of Colorado and Nevada. But he lost in most of the South, including North Carolina and Arkansas, where the electorate remains uneasy about legalizing millions of illegal immigrants.
His aggressive push for a path to citizenship isn't necessarily going to help Sens. Kay Hagan, D-N.C., and Mark Pryor, D-Ark., who might face tough re-election prospects in 2014.
"If they vote for it, Republicans will add it to the litany of things that they supported the president on," said Jennifer Duffy, an analyst at the nonpartisan Cook Political Report.
Immigration reform supporters think they can get enough Democrats to pass the bill, but Israel Ortega, the editor of Libertad.org, the Spanish-language website of the conservative research center the Heritage Foundation, said it would take only a few reluctant Democrats to wreck the bill.
It's happened before.
About two years ago, five Democrats joined Senate Republicans and doomed an effort that would have given hundreds of thousands of young illegal immigrants a path to legal status if they enrolled in college or joined the military. The Democrats were Hagan, Pryor, Ben Nelson of Nebraska, and Montana's Jon Tester and Max Baucus, who is also facing re-election in 2014.
Had all five voted the other way, the bill, known as the DREAM Act, would have reached the Senate floor and could have passed by a simple majority. The House of Representatives already had passed the measure.
Dozens of young advocates crowded the galleries above the Senate floor in December 2010 in support of the bill. Many wore graduation caps and gowns. They held hands as the senators cast their votes.
"It was pure devastation," said Gaby Pacheco, a 28-year-old Miami-based advocate who was among the students.
Pacheco said she and other students would never forget the vote. They plan to keep pressure on Hagan and other Democrats who they fear might oppose another immigration proposal.
"It's not all just bad Republicans and good Democrats," she said.
Democratic Sens. Mary Landrieu of Louisiana and Mark Begich of Alaska are two other senators facing re-election who are being closely watched on this issue.
A member of the Homeland Security Committee, Begich said last week that he liked the direction of the Senate bipartisan plan, which included a path to citizenship and actions to make the borders more secure. Before he decides, however, Begich wants more specifics on how the legalization process would work.
One of the Democratic leaders of the bipartisan Senate group working on immigration, Charles Schumer of New York, said it was too early to worry about how this bill might affect conservative members of the party in the next election.
"Look, we're trying to come up with a bipartisan bill," he said. "We'll worry about counting the votes once we have a bill. We still have a ways to go."
Undoubtedly, if the immigration proposal proceeds, there will be pressure on these conservative Democrats to support it. How much pressure will depend on the election competition they're expected to face next year, Duffy said.
If there's a strong challenge from the right, Hagan and Pryor may be inclined to vote against a proposal that includes a path to citizenship. But if it looks as if they will face little or no competition, Democratic leaders make it tougher for them to say no, Duffy said.
"It's all about counting noses and who they need," she said.