Prosecutors in the Southern District of New York want you to know the real problem with President Trump paying off a porn star to keep her quiet about their extramarital fling is that his shady lawyer didn't use campaign funds to do it.

The legal reasoning here is tendentious and the implications are absurd, and it wouldn't be treated seriously if it were not a Republican politician being targeted for potential prosecution.

When producing and buying time for a campaign ad, the law says a candidate must pay through his campaign. This ensures disclosure of who is funding the candidate’s campaign. The same is true for other campaign expenditures such as renting an arena for a rally, hiring security details for the candidate, and so on.

Trump lawyer Michael Cohen now contends in his guilty plea that he broke the law by paying hush money to two women who say they had sex with Trump. The argument goes that these payments, from corporate accounts, were secret expenditures by the campaign.

Maybe Cohen has more evidence, but if not, the grounds for saying Trump broke a law are laughably flimsy.

The argument is that since the hush money was paid to “influence” the election, it was a campaign expenditure. But by that logic, every dime Chris Christie spent to lose weight before his 2016 run — the diet books, the StairMaster, the bariatric surgery — was a campaign expenditure. If Christie bought a SlimFast shake with his personal money, was he a felon?

Former Federal Election Commissioner Bradley Smith posited another hypothetical: “If a business owner ran for political office and decided to pay bonuses to his employees in the hope that he would get good press and boost his stock as a candidate, would that be a campaign expenditure, payable from campaign funds?”

If a candidate who normally gets a $12 haircut shells out $40 for a better cut, is he a criminal for paying out of his own pocket even though the idea is to look sharp in front of news cameras? If a candidate pays a contested past-due personal bill only to make the headache go away before the debates begin, is he legally required to pay out of his campaign coffers?

Paying such expenses out of campaign funds would probably be unethical and possibly be illegal. If you're damned if you don't and damned if you do, then it's a pretty good sign that either the law is an ass or someone is not reading it honestly.

Cohen pleaded guilty to this campaign finance violation to avoid prison time for more serious tax evasion issues. Just because he pleads guilty doesn’t make Trump a criminal.