SurveyUSA approval polls for US Senators

Late last week SurveyUSA released approval ratings for all 100 US Senators, as part of a long-term tracking program they've been doing for several months of senators and governors. On the home front, there were real mixed signals for both our senators. Patty Murray has a decent 52/37/11 score, and Maria Cantwell has a slightly lower 47/37/15 score. Since Cantwell is the one with the current target on her back, hers is the one that is important to decipher. SUSA does a good job, and always has, of breaking down their results by demographics, but that often just complicates the interpretation of the numbers. Most factoids are open to interpretation of whether Cantwell is in a good or poor position leading up to her run for reelection, but the following are indisputable:

Positives:
-Near 50%
-Currently winning self-described moderates and Independents

Negatives:
-Current numbers increasingly worse compared to previous two results
-Poor ratings amongst the 18-34 age group and Hispanics
-13th least popular senator in poll

In short, it depends how one views the poll on whether it's positive or negative. Partisans of both sides will probably claim victory, but it is still apparent that Cantwell is vulnerable at the very least.