Washington, Oct. 21 -- For Mick Mulvaney, the hits just keep on coming. First, President Donald Trump's acting chief of staff stirred up a tempest by acknowledging that the administration had held up aid to Ukraine in part to prod that country to investigate Democrats and the 2016 elections. Then Mulvaney went on television Sunday to defend his boss in effusive terms - and ended up making a new problematic comment.

Explaining why Trump had tried to steer an international summit to one of the president's own properties before giving up on the idea, Mulvaney said Trump "still considers himself to be in the hospitality business." That did nothing to allay concerns that the president has used his office to enrich his business interests.

The...