That was the message for Dems in this election cycle straight from political writer David Mark on the Daily Show tonight, promoting his new book, “Going Dirty: The Art of Negative Campaigning.” When Jon Stewart asked Mark about Bob Woodward’s still number one “State of Denial,” he commented with a smile on his face that the veteran WaPo journalist is a like a “weather vane” who covers the Bush administration based on whichever way the political wind is blowing. You can catch more of Mark’s political observations when he debuts later this fall with the new Capitol Leader newspaper.