But if he keeps it under wraps, Democrats will claim Mr. Trump is hiding something. By releasing the transcript to the public himself, he counters that charge and gives Democrats little more to investigate. He would also be daring Democrats to impeach him based on a phone conversation whose content Americans will be able to evaluate for themselves. If the conversation is as straightforward and “perfect” as Mr. Trump claims, Democrats will struggle to make it look impeachable to non-fanatical voters.

Democrats will also face a choice of how to handle Mr. Biden’s conflict of interest when as vice president he demanded that Ukraine fire a prosecutor investigating corruption, including a company that hired Hunter Biden as a director. Will they defend Mr. Biden’s actions as appropriate but impeach Mr. Trump for asking Ukraine to investigate corruption and the Bidens? That would certainly be a fascinating political straddle.

Many on the left may not mind if the Ukraine uproar also takes down Mr. Biden’s presidential candidacy because it would clear the nomination path for Elizabeth Warren or Bernie Sanders. But that might not thrill the House Democrats in swing districts who might then face a tougher re-election fight. Let’s see the transcript and watch if Democrats have the courage of their impeachment dreams.