Don’t build your fortress on quicksand.

That’s been my unsolicited advice for President Trump and his legal team. You always want the foundation of your defense to be something that is true, that you are sure you can prove, and that will not change.

Instead, the president and his team decided to make a stand on ground that could not be defended, on facts that were unfolding and bound to change. Last night, that ground predictably shifted. In a soon-to-be-published memoir, former White House National Security Adviser John Bolton asserts that the president withheld $391 million in defense aid in order to pressure Ukraine into investigating Trump’s potential 2020 election opponent, former vice president Joe Biden.

LEAKED BOLTON CLAIMS FUEL FIERY NEW CLASH OVER IMPEACHMENT TESTIMONY

For months, I’ve been arguing that the president’s team should stop claiming there was no quid pro quo conditioning the defense aid Congress had authorized for Ukraine on Kyiv’s conducting of investigations the president wanted. Trials and impeachment itself are unpredictable. You don’t know what previously undisclosed facts might emerge during the trial that could turn the momentum against you. So you want to mount your best defense, the one that can withstand any damaging new revelations.

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Here, the president’s best defense has always been that Ukraine got its security aid, and President Volodymyr Zelensky got his coveted high-profile audience with the president of the United States (albeit at the U.N., rather than at the White House). Kyiv barely knew defense aid was being withheld, the very temporary delay had no impact whatsoever on Ukraine’s capacity to counter Russian aggression, and Zelensky was required neither to order nor to announce any investigation of the Bidens.

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