Donald Trump now has the Senate nominees he wanted to win Republican primaries. We’ll soon learn if they can win in November, or if candidates with little experience and a focus on Mr. Trump’s 2020 grievances will cost the party majority control for another two years.

The GOP dodged one potential Senate debacle last week when Eric Schmitt, the state attorney general, defeated former Gov. Eric Greitens in Missouri. Mr. Greitens carried more baggage than the Queen Mary, but the GOP had to spend some $10 million in advertising to keep him down in the polls lest Mr. Trump endorse him. In the end Mr. Trump played for laughs by endorsing “ERIC” the day before the election.