One option off the table is converting that money to a Trump presidential campaign, according to federal election lawyers. If Mr. Trump decides he must upstage the midterms and announce this fall rather than waiting, he’ll immediately need to file a new committee for his presidential campaign to pay his political expenses. That’ll mean asking for donations at the same time GOP candidates for Senate, House, governor, state legislatures and local offices are scrambling for dollars to win midterms. Candidates, donors and grass-roots activists are sure to be angry that the former president put his personal interests above those of the party if he announces before the midterms.

So what can Mr. Trump use his existing cash stash for? Well, financially supporting other candidates, but he hasn’t shown much interest in that so far. Save America, the former president’s leadership PAC, has given $5,000 each—the maximum by law—to 60 House and 13 Senate candidates. This $365,000 is a pittance, and it’s impossible for him to use up Save America’s remaining $103.1 million this year simply with direct contributions. If Republicans were running candidates for every House and Senate seat this year and Mr. Trump gave each $5,000, that would amount to only $2.35 million…

If Mr. Trump doesn’t start actually deploying these funds to help candidates he’s backed for Congress, governor and other statewide offices, donors might not keep giving to the former president’s causes. Trump-endorsed candidates might start to wonder how strong an ally the former president really is, beyond lending his name in a primary.