More bad news for Democratic U.S. Sen. Maria Cantwell today. The latest Rasmussen poll shows the race between her and former Safeco CEO and Republican Mike McGavick tightening to 46 percent to 41 percent, with a margin of error of plus or minus 4.5 percent. Rasmussen’s methods are controversial because they rely on robo-calls rather than live pollsters, but the tightening trend is not unexpected. Cantwell is having major problems with her base over the war in Iraq, and McGavick is positioning himself as a civil centrist. When you consider that McGavick ran former Republican U.S. Sen. Slade Gorton’s infamous, vicious campaign against former Gov. Mike Lowry, it’s a little hard to take his civility claims seriously, but no one ever said the voting public wouldn’t buy snake oil from a good salesman.