Ex-Solicitor General details why the National Enquirer ruling shredded one of Trump's last defenses

Former Acting Solicitor General Neal Katyal explained exactly how Donald Trump's second-to-last defense against being indicted when AMI struck a no-prosecution plea deal in Michael Cohen's sentencing.

Trump's defenses surrounding accusations that he violated campaign finance laws with "hush agreements" to two women are "crumbling rapidly," Katyal wrote in a lengthy Twitter thread on the subject.

The former solicitor general predicted in the thread that "the only thing" Trump has left is the concept that a sitting president can't be indicted.

Katyal reiterated a point he made in a May New York Times column -- that if a sitting president truly can't be indicted, "that could actually hurt Trump in huge ways."

Katyal noted that although the presidency "is a get out of jail free card for crimes you committed to get there," the Justice Department's two rulings on the indictment of presidents only apply to federal rules. In the case of Cohen and AMI, the charges "have a state component" and were brought by the Southern District of New York, so DOJ rules may not apply.

As he noted in May, Katyal pointed out that if Trump truly can't be indicted, the onus is then placed on Congress to investigate him and potentially impeach him -- a dangerous prospect given that Rep. Jerry Nadler (D-NY) is "a brilliant and dogged investigator."

He also noted that the DOJ's presidential indictment policy is "generic" and that special counsel Robert Mueller could "obtain permission to indict Trump" -- particularly if he insists on not testifying so as to avoid the "perjury trap" his lawyers keep warning about.

Though it remains unclear whether Acting Attorney General Matthew Whitaker or Deputy AG Rod Rosenstein are overseeing Mueller's investigation, either could "conclude that in America, no one is above the law" and authorize Trump's indictment.

Finding that workaround, "particularly in a world of witness tampering, fake AGs installed [and] now serious allegations of lying by President, and indeed, felonies," may be "Mueller's best option," Katyal mused.

"Trump has to know all of this," he added, "at least if he has decent counsel."

He may conclude, "as Spiro Agnew did before him," that his one card left to play is to "resign and plea to avoid jail time."