By Kevin McDermott

Donald Trump's presidential campaign has paid $35,000 to a mysterious firm with ties to Missouri's raucous Republican gubernatorial primary race, and no one can figure out why.

Our national media colleagues are certainly trying. As of Tuesday, numerous news platforms -- including CBS, BuzzFeed, Slate, The Hill and Vanity Fair -- were all asking (as a Washington Examiner story puts it), "Is Trump doing business with a fictional ad agency?"

It's all the result of the release Monday night of the campaign finance records of Trump, the presumptive Republican presidential nominee. The big headline out of that data dump was that Trump's campaign is sitting on just $1.3 million, which is peanuts for a presidential bid. Presumptive Democratic nominee Hillary Clinton has more than $42 million.

A side story, apparently first reported Tuesday by ThinkProgress, is that, buried in almost 1,700 pages of campaign records, is $35,000 in payments from Trump to an entity called "Draper Sterling," for "web advertising."

The name is clearly a play on the two main characters from the hit AMC series "Mad Men" (starring St. Louisan Jon Hamm as the dapper and deeply flawed 1960s ad-man Don Draper).

The firm's odd name caught reporters' attention. What kept it is the fact that there's only a little public mention anywhere of what "Draper Sterling" is. And that little mention is in a federal election fraud complaint.

We know a little something about all of this at the Post-Dispatch, because the Draper Sterling "fictional ad agency," or whatever it is, is tied to a federal PAC that big-footed into Missouri's race for governor earlier this year.

This gets complicated. Stay with us:

--"Patriots for America" is a federal PAC run by Adam McLain, who is a former staffer of Missouri Republican gubernatorial candidate John Brunner.

--The PAC last year set up an attack website against Missouri Republican candidate Eric Greitens. Brunner has denied he had anything to do with it, even though his former staffer ran it. Greitens alleged otherwise, culminating in a seething, secretly recorded phone argument between Greitens and Brunner.

--McLain, of the Patriots for America PAC, is the brother of Paul Holzer, according to the ThinkProgress report. Holzer also has worked with the Brunner campaign.

--Holzer has been a business partner with one Jon Adkins, who is the founder of Draper Sterling, according to corporate records.

--In addition to paying Draper Sterling $35,000, the Trump campaign paid Adkins and Holzer $3,000 each, for "field consulting," according to Trump's records.

--Patriots for America -- the PAC set up by Brunner's other former staffer, McLain, to go after Greitens -- has been hit with an FEC complaint, filed by a Greitens supporter, questioning why the PAC owes $56,234 to Draper Sterling for "business consulting."

"To recap, there is a nexus between Jon Adkins, Paul Holzer and Adam McLain that meets at the mysterious Draper Sterling," writes Judd Legum in the ThinkProgress piece that flagged the Trump expenditure.

"We still aren't sure what Draper Sterling actually does, but these individuals are going to considerable lengths to obfuscate their activities."

A Brunner spokesman said his campaign has had no contact with McLain or Holzer since September 2015.

In addition to Brunner and Greitens, Missouri's GOP primary field includes former state House Speaker Catherine Hanaway and Lt. Gov. Peter Kinder. The winner of the Aug. 2 primary will likely face Democratic Attorney General Chris Koster in the Nov. 8 general election.

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