That seems to be the underlying justification for Donald Trump to be using campaign funds — and money from the Republican National Committee — to pay his legal bills around the Russia investigations. Not being in jail (or impeached) would seem to be sine qua non for being reelected in 2020.
How those folk who donated to the campaign (or to the party) with the thought that it would actually go to normal election efforts feel may be a different matter, though presumably they are enough of a “Stand by your man” guy to figure Trump can spend their donations however he wants. And given that he has $12M in the bank with his re-election committee, he can afford a lot of billable hours.
Trump using campaign, RNC funds to pay legal bills from Russia probe: sources
U.S. President Donald Trump is using money donated to his re-election campaign and the Republican National Committee to pay for his lawyers in the probe of alleged Russian interference in the U.S. election, two people familiar with the matter told Reuters.

Running for office can be a profitable career even if you lose. Just pay some stooge millions of donated dollars to run a campaign badly, then split the loot afterwards.
+Travis Bird I wonder if that was his original plan, but they encountered a Springtime for
HiitlerTrump moment?+Valdis Klētnieks I'm sure he had all the options covered.
+Travis Bird Don't bet on it – if he had a the options covered, he'd not have a special counsel chasing him….