Republicans could relinquish a significant portion of the gains they made in the midterm elections if they "allow" the omnibus spending bill to pass, Sen. John McCain said Wednesday.

The Arizona Republican said Tea Party activists who helped the GOP make large inroads on Democrats are "enraged" about the $1.1 trillion measure to fund the government that contains nearly $8 billion in earmarks. 

"They gave us a second chance last November. ... And if we Republicans allow this thing to go through, then I'm not sure they're going to give us another chance," McCain said during an interview with Fox News's Sean Hannity

McCain's comments put in stark relief the political dangers Republicans — and some Democrats — could face if the appropriations bill in its current state passes the Senate during the lame-duck session.

The 2008 GOP presidential nominee said there are five or six senators from his party who "may vote for it," leading him to say that the bill "may pass." 

Senate Republican Leader Mitch McConnell (Ky.) has introduced an alternative to the omnibus: a one-page continuing resolution that would fund the government until Feb. 18, at which point the new Congress could pass a comprehensive spending measure.

McCain also warned Democrats they could feel voter backlash if they support the bill. Democrats must defend 23 Senate seats, some in swing and red states, in the 2012 elections.

The senator urged Tea Partiers to voice their opposition to the bill even more loudly. 

"I was on the phone with the Tea Partiers all over Arizona today," he said. "They are enraged. They are outraged. I want to see an uprising all over this country from the same people who caused our [gains]."