Bill Halter’s support for the public option symbolizes a thread of liberal politics that will last well beyond this current Congress, regardless of what happens with health care. The public option now becomes a litmus test on the Democratic side in political campaigns.

Halter told Arkansas reporters today, as seen in the video to the right, that he would favor “an option for members of the public to voluntarily buy into a program like Medicare. And I think you’ll see that people understand that, if it’s voluntary, if it’s something that they can buy their way into, if it’s something that, where the costs are met, I think you’ll see a lot of support for that.”

Following up on this, Greg Sargent reports that Halter would also back the use of reconciliation to pass a health care bill, and speaking of the public option, he said, “I think that that’s gonna be an issue of course in this campaign.”

I don’t know a ton about Halter, but his willingness to back a public option makes clear that he feels support from a national base is conditioned on his answer to that questions. The attacks from the netroots on Blanche Lincoln already reference her work in killing the public option as “her greatest accomplishment” as a senator. Clearly, if Democrats want support from a healthy portion of the base, they need to support the public option during their campaigns.

That’s what’s also driving the sitting Senators to endorse the public option as part of a reconciliation sidecar bill (the total number of Democrats in support has grown to 33). They don’t want to raise the ire of the base, and would rather bask in their applause.

Whether this gets you to majority support for the measure in this bill is unclear, and frankly, somewhat remote. But its resonance as an electoral issue is unquestionable. And over time, that can translate into eventual support.

This will not be the last primary where the public option becomes an issue, put it that way.