While the rest of the country copes with the weather and makes holiday plans, Washington's "political class" is buzzing about brain surgery. South Dakota Democrat Tim Johnson is in stable condition after surprise brain surgery Wednesday night. Nevada's Harry Reid has been visiting George Washington University hospital every day and says Senator Johnson looks "really good" to him. But the same may not be true of the one-seat Democratic majority that Reid is expected to lead as Johnson's sudden ailment could alter Democrats' one-vote balance of power in the US Senate. Or could it? The Senate is bound by tradition and, back in the 40's, one member served four years without ever attending a session. In these polarized times, will the Upper House maintain its historic gentility or give way to the partisan demands of the moment?