Democrats have tried to defend pursuing their impeachment inquiry behind closed doors by comparing it to a grand jury inquest. I’ve given a bunch of reasons why this analogy is ill-conceived. There is one way, though, in which it is apt: With the grand jury as with politics, complaints that an investigative process has been flawed virtually always fail.

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It is a lesson the White House and congressional Republicans had better internalize quickly.

Prosecutorial misconduct in grand-jury proceedings is almost never a basis to dismiss an indictment or throw out a conviction. The reason is straightforward: Even serious missteps by the investigators do not excuse or erase the serious misconduct that is under investigation. Consequently, if an accused ultimately receives a fair trial with sufficient due-process protections, a court will not throw out the case based on violations at the grand-jury stage.

NEWT GINGRICH: PELOSI ANNOUNCES TRUMP IMPEACHMENT INQUIRY VOTE – HERE'S WHAT I AM ON THE LOOKOUT FOR NOW

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That doctrine surely applies to impeachment. It is political, not legal, in nature. Unlike a criminal defendant, the president does not have an array of constitutionally mandated due-process protections. Our law vests the House with the whole of impeachment power. No court may tell the House how to conduct impeachment, and the House need only afford the president whatever minimal protections lawmakers think the public wants him to have if the proceedings are to be accepted as legitimate.

Moral of the story: Better get about the business of figuring out the best substantive defense to the charges that House Democrats are preparing to lodge. The president and his allies are not going to win this on process grounds.

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