The Democratic National Committee has seriously upped its ad campaign against John McCain, with the latest FEC filing showing a $500,000 buy to run the spot on the economy that they previewed over the weekend.

With the Democratic candidates still beating each other up, the DNC has had to step in and do some of the heavy lifting in taking on John McCain rather than let him enjoy a free ride in the press. And this is not a small problem, either -- the DNC has been the one area of Democratic fundraising to seriously lag behind its Republican counterpart.

A DNC staffer told us that the ad will run on national cable.