Senate Majority Leader Harry Reid is drawing a line in the sand on any congressional immigration reform proposals: No citizenship, no bill.

“There will be nothing done in my Senate [on immigration reform] without a pathway to citizenship,” the Democrat told the Las Vegas Sun on Thursday.

This could be a problem in the Republican-controlled House, where members have expressed reservations about letting any of the estimated 11 million illegal immigrants who could benefit from an immigration reform bill become citizens.

The Obama administration wants immigrants who overstayed their visas or crossed the border illegally to prove they've resided in the country for several years, have not committed any crimes and will pay any owed back taxes. In exchange, they'll receive temporary legal status that could lead to citizenship in about 15 years.

Republican House Judiciary Chairman Robert W. Goodlatte of Virginia said on Wednesday that he would most likely not sign on to a citizenship-inclusive reform bill, but would consider giving noncitizen legal status to illegal immigrants.

But it's possible that Marco Rubio, a Republican senator from Florida who won office with support from the tea party, may be able to attract more conservatives to an immigration plan that includes citizenship. In an interview with conservative commentator Laura Ingraham on Wednesday, Rubio brushed off her theory that Democrats support immigration reform because they want a "vast path to voting rights" for immigrants in order to lock in more political support.

"Here's the bottom line: This country needs a legal citizenship system that works," Rubio said. He added that any path to citizenship would be gradual. Conservative Fox News host Bill O'Reilly, meanwhile, called Rubio's plan "fair" when the senator came on his show this week.