Bernie Sanders has become a millionaire, and he did it by selling his new book! In blunt fashion Sanders explained his get rich strategy: “I wrote a best-selling book. If you write a best-selling book, you can be a millionaire, too.” NYTimes.com

During the 2015 primary campaign the pre-millionaire Bernie employed a book buying/selling strategy that never would have gotten him rich but might be worth a glance now as the crowded Democratic primary race heats up.

According to FEC filings, the Sanders campaign bought thousands of dollars of his books. Sanders spent almost $445,000 of his donors’ campaign funds with Verso Books, the publisher of Outsider in the White House, which was a quick re-working of his earlier Bernie book: Outsider in the House. I mentioned the purchase in a diary: Campaign dollars to donuts back then without really taking aim at it; I don’t recall it making any waves in that long campaign.

Buying your own books with your campaign-donor dollars sure looks a little shady, but it isn’t unheard of or apparently illegal. But since the Citizens United decision super-PAC dark money is running rampant in campaigns — and with the six-member Federal Election Commission often deadlocked, enforcement is spotty.

In recent years candidates for national office have been regularly buying their own books (aka 300-page hardcover party favors) with campaign money. For instance in 2015 the csmonitor.com reported that Senator Ted Cruz’s campaign paid $122,252.00 to the publisher of  his book A Time for Truth. Ben Carson, Sarah Palin, Herman Cain and Mitt Romney all used campaign or PAC funds to buy their own books.

The FEC found a variety of likely violations made by Newt Gingrich’s 2012 presidential campaign over a book-promotion deal and campaign funding. After three years of wrangling, a deadlocked vote between Democratic and Republican Commission members halted any possibility that the FEC would be investigating the former Speaker of the House.

Now, I’m fine with Bernie Sanders in the millionaire club, despite what some see as hypocrisy. But he really shouldn’t be in that particular book club.