INDIANAPOLIS -- The issue of national health care reform could endanger the political future of Indiana Sen. Evan Bayh.

The moderate is in hot water with liberals for his failure to endorse a reform bill, 6News' Norman Cox reported.

As recently as two days ago, Bayh said he might not be able to support a motion to proceed with a floor debate on health care if it's too expensive.

This week, the liberal group MoveOn.org delivered petitions to Bayh's Indiana offices signed by 244 people identified as former Bayh donors and volunteers. They said if he votes to sidetrack health care reform, they're finished with him.

"We want him to go with the party and to vote for cloture so that we can get this thing moving and done," said Joyce Moore of MoveOn.org. "We need health care reform, and we want him to get off the fence."

For years, liberal politicians in Indiana have bitten their tongues when Bayh did things distasteful to them, like cutting welfare and Medicaid benefits. But some are now starting to speak out.

"Our U.S. senator seems to always want to be in the middle of the road," said Rep. Charlie Brown, D-Gary. "And all of us know that if you stand in the middle of the road, you're going to get hit in the traffic going in both directions."

But Democratic State Chairman Dan Parker said Bayh has the majority of Hoosiers in his corner, and predicted he will keep them there.

"He's going to do what is in the best interest of Hoosiers, the right thing," Parker said. "This is a big issue. The Democratic Party has focused on this issue for 60 years. He understands how big of an issue it is not only to the country, but to the party, and he's going to do the right thing."

Indiana University political science professor Bill Blomquist said it is a major issue for many individuals, but not likely serious enough to topple Bayh.

"There are so many advantages for an incumbent senator like Sen. Bayh within the Democratic Party," Blomquist said. "That the ability of someone to, for example, successfully challenge him in a primary or try to take the nomination of the Democratic Party away from him, are really, really slim."

Bayh has been a senator since 1999, after serving two terms as Indiana governor.