Several Democratic senators voiced optimism on Sunday that Congress would pass a health care bill containing at least the germ of a government-run insurance program. Their expectations were grudgingly seconded by Senator John McCain, the Republican presidential candidate in 2008.

“I think the Democrats have the votes, and in the House, Blue Dogs bark but never bite,” Mr. McCain said on CBS’s “Face the Nation,” using the nickname for conservative Democrats . “So I don’t think they have a problem over in the House side. In the Senate I think the Democrats are very aware that they don’t want a repeat of the Clinton failure in 1994. So I think it’s very likely they will get something through. But it’s not clear to me what it is.”

Mr. McCain of Arizona was among the senators appearing on the Sunday morning television talk shows, which again focused on health care and Afghanistan. The senators’ remarks came after Harry Reid, the Senate majority leader, told President Obama on Thursday that he would try to press for a government-run insurance program. With five health care bills under consideration in both branches of Congress, Speaker Nancy Pelosi has already said that the House version of the legislation would include the so-called public option, but other key senators have previously said it would be difficult to round up 60 votes needed to guarantee that the legislation would not be blocked by a likely Republican filibuster.

One question is what kind of public option  a full-blown government-insurance plan, or something like a “trigger” provision, which would create a government-run or nonprofit plan if insurance companies did not cut costs within a set period of time or under certain conditions.