D.C. paper Roll Call has an article today showing that Democratic candidates' ability to win over even a small slice of Republican voters diminished considerably last election cycle, which may spell trouble for vulnerable Democrats in 2012, including Sen. Maria Cantwell.

Re: Cantwell, Roll Call reoports:

It’s unclear whether this trend could widen the Senate playing field for Republicans. Sen. Maria Cantwell (D-Wash.) received 11 percent of the GOP vote when she was elected by less than a point in 2000. She received 9 percent in her easier 2006 re-election. Last year, Sen. Patty Murray (D-Wash.) won re-election, but with just 4 percent of the Republican vote.