Yet the way the president told it today, it sounded as if the Republicans are responsible for the tenor and volume of it.

Off the 68,443 ads that Obama has run on TV (local broadcast, national network & national cable) in the 30-day period ended July 2, 52,016 had an “anti-Romney message” — 76 percent of the total, according to New York-based Kantar Media’s CMAG, which monitors campaign advertising.

Obama’s negative ads have overtaken his positive ads. Since April 10, when Republican Rick Santorum’s exit essentially made Romney his party’s presumptive nominee, Obama has run 112,202 ads, of which 58,151 were anti-Romney and 54,051 positive.

So Obama’s been running heavily negative lately.