By Kellyn Brown

A narrative is emerging from Montana’s 2012 U.S. Senate race that contrasts with the last general election when dozens of new lawmakers were swept into office riding a wave of Tea Party support.

Instead, the early plotline for this contest pitting incumbent Democratic Sen. Jon Tester against Republican Rep. Denny Rehberg is focused on the ways in which they oppose their party’s resolute policy positions.

Tester has been identified by his “moderate politics.” Rehberg, the New York Times pointed out, “has bucked the more conservative corners of his party in recent months.” Whether these characterizations are deserved, both men have drawn heavy criticism from their base recently and that – in Washington, anyway – makes you “centrist.”

One example occurred in late 2010, when Tester voted against the DREAM Act, which would have provided a path to citizenship for children who came to the country illegally. Some of the harshest criticism for that vote came from Markos Moulitsas, founder of the highly trafficked liberal Daily Kos blog.

“Not only will I do absolutely nothing to help his reelection bid,” he wrote, “but I will take every opportunity I get to remind people that he is so morally bankrupt that he’ll try to score political points off the backs of innocent kids who want to go to college or serve their country in the military.”

In response, Tester called the act “amnesty” for illegal immigrants.

More recently and perhaps more surprisingly, Rehberg voted against the budget plan advocated by his colleague Wisconsin Rep. Paul Ryan, which was supported by every Republican in the House of Representatives save for four. It was also largely backed by the Tea Party and Rehberg is a member of the “Tea Party Caucus.”

But the congressman expressed concerns over significant changes to Medicare and argued that the measure was rushed.

“There are still too many unanswered questions with regard to Medicare reform, and I simply won’t support any plan until I know for a fact that Montana’s seniors will be protected,” he said.

That did little to placate conservatives. The Washington Examiner blogged: “A Republican runs to the Left to win in … Montana?” And Eric Olson, co-founder of the Tea Party group Montana Shrugged, said Rehberg is simply “trying to vote for a political election now” and even floated the idea of someone challenging the congressman in the Republican primary.

Chances are, these veteran politicians will sail through their respective primaries with little effort. And while neither will admit it, this campaign pivoted to the general election the day Rehberg announced he was running for Senate.

Rehberg’s vote against the Ryan budget makes sense and helps him deflect criticism that he wants to gut Medicare in a state that is older and has more Medicare recipients than the national average.

Tester’s vote against the DREAM Act helps him avoid the line of attack that he favors amnesty for illegal immigrants. And the majority of Montanans likely support his position.

Whether their respective votes delude some of their base’s enthusiasm may matter less to them in a race that is polled at a dead heat and may tip the balance of control in the Senate. From now until November 2012, the campaigns will aim to capture that elusive “populist” appeal, which is sure to anger some liberals and conservatives but is perhaps a better strategy for winning a close election.

There is still plenty to differentiate Tester and Rehberg (votes on health care reform and raising the debt ceiling). But in a race expected to attract loads of outside money used to paint both men as “extreme,” each has begun inching further from the left and right.