To impeach or not? Why Democrats have been keeping things fuzzy.

Among Democrats in Congress, a new impeachment divide is emerging: Not only do they remain deeply split over whether President Donald Trump ought to be impeached, they can’t agree on whether they have, in fact, already begun the process.

As the various investigations, hearings, and court battles heat up, Democratic leaders seem unable to decide whether it’s all still a prelude – or if an “impeachment investigation,” as House Judiciary Committee chair Jerry Nadler of New York now terms it, is actually underway.

“If we have to go there,...