The long political career of Saxby Chambliss has been something I've observed with reactions that could almost be called bipolar. There's rarely been any in-between: Most of the things he's done or said have struck me as either very, very good or very, very bad.

His first Senate campaign, against incumbent Democrat Max Cleland, is still my pick as the low-water mark of modern politics. It's worse even than Lyndon Johnson's 1964 nuclear Armageddon ad against Barry Goldwater, and that one came out when I was 12. Visually linking an honorable Vietnam vet to Saddam Hussein and Osama bin Laden makes rock bottom look like a plateau.

His bullying of witnesses at Capitol Hill hearings on the tragic Imperial Sugar explosion and fire near Savannah was inexcusable. If that wasn't a powerful man trying to publicly intimidate people whose testimony indicted the depraved negligence of a favored constituency, it was a convincing imitation.

And he again introduced, as he has every year, the Orwellianly named "Fair Tax," which would in effect replace all other major forms of taxation with sales tax -- or, as Republicans prefer to call it now, "consumption tax." (A Georgia legislator is pushing the same thing at the state level. If Republicans sincerely want to shake the image of coddling the rich at the expense of the working poor, they really do need to kick their addiction to regressive taxes.)

Yet in recent years, if you had to single out a lawmaker who was swimming against the tide of everything wrong with Washington, it would be hard to miss Saxby Chambliss.

It's a familiar truism that a politician becomes a "statesman" when he or she dies, retires or, in this case, decides this will be the last act. Chambliss announced Friday that he will not seek reelection to a third Senate term when his current one expires in 2014.

After 20 years on the Hill, in both houses of Congress, Chambliss issued a statement that said, in effect, he's had it. He's frustrated with what he says is a leadership vacuum in both the White House and Congress, and the hyper-partisanship that has all but ground effective governance to a dead halt.

"The debt-ceiling debacle of 2011 and the recent fiscal cliff vote showed Congress at its worst," the statement said, "and, sadly, I don't see the legislative gridlock and partisan posturing improving anytime soon."

That's a depressing, if not surprising, assessment, especially from Chambliss. Because the very best of his political legacy should be his attempts, and those of colleagues on both sides of the widening partisan divide, to build consensus and actually get something done about things that matter.

In that effort, Chambliss has managed to anger both sides, which in Washington politics is usually evidence that you're doing something right. His "Gang of Six" and similar bipartisan efforts at budget compromise are implicit reaffirmation of what now looks like a quaint notion: That those in the other camp are political opponents, not minions of Satan.

Used to being a target of the left, Chambliss has more recently been shouted at from the echo chambers of Radio Right, and tarred with the mortal sin of ideological impurity by the wing-nut fringe of his own party. (Speaking of which, did you hear the latest from Georgia's own Rep. Paul Broun, R-Neptune? He says President Obama is guided only by the "Soviet constitution." I think the congressman is finally spinning out of orbit. Good.)

Apparently Chambliss' unforgivable efforts at bipartisanship mean he isn't "conservative" enough, further proof that the word has been stripped of all coherent meaning. Rumors of intra-party challenges have been swirling for a long time, not that Chambliss was very concerned even before his decision to call it a career: "Lest anyone think this decision is about a primary challenge, I have no doubt that had I decided to be a candidate, I would have won re-election." I have no doubt he's right.

It will be interesting to see what Chambliss does over his remaining two years in the Senate, now that he's been freed from most purely political constraints. Regardless of the extreme political highs and lows of his career, his efforts at bipartisanship matter, and profoundly. In a political climate so divided it seems close to irreparable fracture, sincere attempts at consensus building probably matter, right now, more than anything else.