If you’re active on Twitter, Facebook or political discussion forums around the web, you might be tempted to think that the MA Senate race between Scott Brown and Elizabeth Warren was already one of the nastiest, down and dirty, rolling in the mud campaigns in the nation. Conservatives not only have a vested interest in hanging on to the traditionally Democratic Senate seat in a deep blue state, but have found in Warren a poster child for nanny state policies and far left liberal ideology. Liberals, for their part, seem to be driven to the brink of insanity at the idea that a dreaded Republican could seize “The Kennedy Seat” and – even worse – see insult added to injury if Brown goes on to win a full term. This leads to some impassioned and frequently brutal verbal assaults on both of them.

But according to a report out this week from Politico, the battle looks quite different if you’re only watching it via television ads in the Bay State.

For the better part of a year, the Massachusetts Senate race between Sen. Scott Brown and Elizabeth Warren has been a paragon of positivity: Two candidates making their case to voters, not a single ugly attack ad. Even super PACs — the masters of doing candidates’ dirty work — have stayed away.

If that all sounds too good to keep up — well, it probably is.

Pretty much all of Brown’s ads have focused on the fact that his policies are better for the state. Warren, when she has anything critical to say, seems to put on airs of a disappointed professor speaking to voters who are the equivalent of thick skulled students.

The consumer advocate’s earlier ads showed her looking straight into the camera, lamenting the country’s failure to create public infrastructure jobs and promote women’s rights.

“Preachy, professorial and petulant” was how some strategists in her own party described the Harvard Law professor’s dozen ads since November.

Since she’s down in the polls, apparently Warren has gotten the memo and decided to come out, er… firing?

Warren took the first shot this week with a spot criticizing Brown for “siding with the big money guys” — mild by negative ad standards, but a departure still.

Wow. That’s really going straight to DEFCON 1, isn’t it? (not)

So Brown is leading, albeit by a slim margin and Warren is going to have to get her hands dirty if she wants to take back that seat. But Brown needs to be careful. He’s not just battling Warren, but the national GOP at the same time. In order to keep the support of the left leaning indies in Massachusetts he has to continue to portray himself as a “go his own way” Republican. You know… one of the good Republicans. Or one of the reasonable Republicans. So coming out too harshly against Warren in the TV ad wars could backfire on him.

Then again, Warren does such a good job of beclowning herself on a daily basis that he may not need to.