Bernie Sanders insists he will go to the bitter end of the Democratic primary process, even after a series of defeats Tuesday pushed the presidential nomination further from his reach.
The U.S. senator from Vermont must decide what to do with the ample cash pile in the hands of his campaign committee, which has proven adept at raking in mostly small individual donations.
Sanders lost four of Tuesday's five primary contests, beating former Secretary of State Hillary Clinton in only Rhode Island. He now trails Clinton by 787 total pledged delegates, according to NBC News.
Considering those results, some have questioned why Sanders remains in the race. On Tuesday night, the candidate said he would stay in to "fight for a progressive party platform," including $15 per hour minimum wage and tuition-free public college, ahead of the party's July convention.
"The people in every state in this country should have the right to determine who they want as president and what the agenda of the Democratic Party should be. That's why we are in this race until the last vote is cast," Sanders said.
Sanders should have money to work with going forward. His campaign committee had about $17.5 million on hand at the end of March, though it is not yet known what it raised and spent in April.
The Sanders campaign did not respond to a request for comment on its finances.
The campaign has shown the ability to raise huge sums, and spend cash quickly. For March, it reported total receipts of $45.9 million and total disbursements of $44.9 million.
But it remains to be seen if Sanders can keep up the fundraising pace as the nomination becomes increasingly less likely. On Wednesday, he told The New York Times the campaign would cut staff and focus more resources on June's California primary.
"He likely can, and will have to, raise additional sums to continue to get his message out to voters, particularly in expensive media markets like California," said Jessica Levinson, a professor at Loyola Law School and vice president of the Los Angeles Ethics Commission.
Sanders very well could spend his remaining cash pushing his policies until the end of the primary process. However, any promise to stay in the race until the end should be taken "with a grain of salt," Levinson said.
If Sanders keeps up his fundraising prowess and eventually drops out, it would put him in a relatively unique position: defeated but with a cash surplus.
So what could he do with the remaining money?
The Federal Election Commission outlines multiple possible uses for a campaign committee's surplus cash. It can become a multicandidate committee and use the money within the rules of those organizations.
Sanders' cash could go to national, state or local party committees or to other candidates. It could also be donated to charitable organizations or state and local candidates, within certain limits.
After clearing some regulatory hurdles, Sanders could also channel it to a possible Senate re-election bid in 2018, said Larry Noble, general counsel at the Campaign Legal Center. The committee would also have the option to return cash to donors, possibly on a prorated basis based on the size of contributions, he added.
Still, Noble noted Sanders "doesn't have any obligation to wind down" his campaign at this point.
Sanders' next test comes Tuesday with the Indiana primary. An average of recent polls shows Clinton with a four-point lead in the state, according to RealClearPolitics.