The American Heartland PAC hit the airwaves last week in Iowa with a television advertisement criticizing a Republican Senate candidate, Mark Jacobs, as a “Texas millionaire” who supported Democrats in the past. The super PAC, which lists a Washington address, spent $140,000 on the ad.

So where did it get the money?

You’ll have to wait until July 15 to find out. Oh, and the Senate primary, in which Mr. Jacobs faces State Senator Joni Ernst and three other candidates, will be held on June 3. It’s a textbook example of how political professionals would want to structure an independent expenditure campaign: no disclosure until after the election is over.

The group’s most recent filing with the Federal Election Commission lists no contributions or expenditures. The money to pay for the ad came in after March 31, and its sources don’t have to be revealed until the next scheduled filing in mid-July. All of which makes finding out about American Heartland PAC a bit tricky, especially for the local news media.