President Trump has said he can deliver “as many votes” as might be needed from Republicans to help Rep. Nancy Pelosi, his chief Democratic nemesis, become the next speaker of the House.

If so, it would be historic — analysts can’t find any modern precedent for a speaker being elected based on the other party’s votes, and indeed, there are only a couple of examples of even a single member defecting.

It’s also not clear which Republicans would be willing to forsake party loyalty and follow Mr. Trump’s advice.

The president has name-checked just one, Rep. Tom Reed of New York, whose office said he’s open to backing the liberal California Democrat, but only if she makes some bipartisan procedural changes.