Sen. Evan Bayh, D-IN, has always been somewhat fiscally conservative --- but lately, we’ve seen that move to the center/center-right even more, with some speculating that he was doing so to prepare for an assault from the right, as he was planning to run for re-election this year.

Most particularly, he has sounded an ever-increasing alarm about rising federal deficits, aligning with more conservative members of the chamber, for instance, to create a debt commission modeled on the military's base closure system. Bayh worked behind closed doors for hours with his colleagues trying to craft the legislation, only to have the rug ripped out by Republicans who once supported the idea but then abandoned ship at the last minute. (GOP’ers said at the time that they did so fearing that the commission would propose tax hikes and not much-needed spending cuts.)

Bayh has consistently spoken against Washington's ability to voluntarily cut spending, so he increasingly favored mandating that action.

The signs of Bayh's discontent with the direction of the economy and with Washington can be seen in his votes over the past year or so, starting with the budget last year -- he was one of only two Dems to vote AGAINST it. In fact, according to a Washington Post analysis of Senate Democrats' voting records late last year, Bayh was the most conservative Democrat, edging out a more high-profile conservative, Sen. Ben Nelson, D-NE. Bayh voted with his fellow Democrats, according to the survey, just 72 percent of the time.

Earlier this year, Bayh voted against his party when Reid tried to bring up a 10-year, $245 billion so-called “doc fix” --- which was designed to stop massive cuts in federal reimbursements paid to Medicare docs. He told me it was solely because the measure was not paid for with offsets (e.g., spending cuts).

And though he voted FOR the $787 billion stimulus bill, he was part of a group (“Gang of 18”) that axed $100 million from the original product produced by leadership, what Bayh at the time called “silly stuff.” And just recently, he expressed regret about the design of the stimulus legislation, saying he wished there had been "more targeted spending" in the bill.

And the senator was one of only two Dems to vote against the $410 billion omnibus spending bill - sending Majority Leader Harry Reid, D-NV, scurrying for days in an attempt to shore of 60 votes to overcome a Republican-led filibuster.

During healthcare negotiations, Bayh made it clear he did not trust that the bill would really hold down deficit spending. He worked with other conservative members to craft a package designed to rein in future costs. He also jumped into the center of the abortion policy storm when late last year, he joined with seven of his Democratic colleagues to tighten controls designed to eliminate any federal spending on the controversial procedure.

Bayh was also known to opposed the so-called "cap and trade" climate legislation proposed by the Obama Administration.

In March of 2009, Bayh quietly assembled a working group of Senate moderates with a goal of crafting “a fiscally responsible spending plan in the Senate,” according to a release from his office at the time. The group was to meet every Tuesday just before the weekly Dem Caucus lunch.

Most recently, when the debt commission failed (though Obama has said he will enact one, albeit with less teeth, by executive order) he joined forces with Sen. John McCain, R-AZ, to introduce a package of deficit-fighting measures.

"We cannot continue to spend what we do not have," Bayh told reporters, as he praised President Obama's intention to enact a 3-year discretionary spending freeze, something Bayh, himself, had advocated in the Wall Street Journal op-ed last September.

The Bayh-McCain Fiscal Freeze Act of 2010 would enact the spending freeze, a moratorium on earmarks until the budget is balanced, and a line item veto for the president, among other mandates.

And Bayh is not just conservative with fiscal policy. He's somewhat hawkish on defense issues, as well. Most recently, he has pushed for the Obama Administration to impose "crippling sanctions" against Iran and strict sanctions for human rights violations by that totalitarian regime.

But he did join forces with Sen. Olympia Snowe, R-ME, a number of years back in an attempt to tie U.S. foreign aid to Iraq to that government meeting a series of benchmarks.

The writing does appear to have been on the wall with Bayh, said several Democratic sources. And one senior Senate Democratic aide with knowledge of the Bayh decision pointed to Reid's move to take hatchet to the $85 billion bipartisan jobs bill crafted by the top Democrat and Republican on the Finance Committee, slimming it down, without GOP consultation, to a mere $15 billion, though he did leave elements that do have bipartisan support. "From what I understand, that really could have been the straw," the aide said.