DFL Senate candidate Mark Dayton has started his advertising blitz, spending more than 300-thousand dollars on television ads running statewide this week. Dayton is the third Democrat to buy up large chunks of airtime before the September primary. Attorney Michael Ciresi has had ads on the air for months, and DFL'er Rebecca Yanisch just finished a big television ad buy. In the latest in our series of Ad Watches, Minnesota Public Radio's Laura McCallum talks with analyst Dean Alger about the Dayton and Yanisch ads...