A key swing vote on healthcare reform said Sunday she would not support a public option "trigger" -- a series of benchmarks that, if not met by a certain time, would authorize the creation of a government insurance program.

"No -- the problem with triggers is that is just delays the public option," Sen. Susan Collins (R-Maine) told CNN's "State of the Union," adding that her major qualm with the public option was its scope and cost.

"People are concerned about the government's role [in healthcare]," she continued. "They’re very concerned we’re not dealing with the No. 1 issue, and that’s the escalating cost of healthcare."

Collins' remark on Sunday could spell trouble for the White House, which has reportedly worked quite closely with another key swing vote -- Sen. Olympia Snowe (R-Maine) -- on that very issue.