WASHINGTON (AP) — President Donald Trump said he was just exercising his right to free speech. Democrats said he was intimidating a witness.

Whichever is the case, Trump’s Twitter assault on an ex-ambassador’s record came with a heavy dose of distortion.

He portrayed her, in a few choice words, as a wrecking ball in every country where she served U.S. interests in a long diplomatic career that has spanned danger zones and emerging democracies.

The tweet jolted impeachment hearings where Marie Yovanovitch was already testifying to the personal threat she has been feeling from the president.

Ove...