The White House declined to comment on the conversation, but the president is expected to help broker a truce between Sanders and Clinton, who have run an increasingly nasty campaign.

Clinton is expected to amass enough support in Tuesday’s primary contests to claim the Democratic nomination.

An endorsement from Obama could come as soon as Wednesday, though the exact timing remains unclear, White House officials say.

But the Vermont senator has pledged to fight all the way until the Democratic National Convention in late July, hoping to pick off enough superdelegates from Clinton to win the nomination.

White House press secretary Josh Earnest on Monday indicated the delegate math is clear cut.

“Certainly somebody who claims a majority of the pledged and superdelegates, you know, has a strong case to make,” he said.

“After the Democratic voters in New Jersey and California weigh in tomorrow, you know, we may have a better sense of where the race is headed,” he said.

Sanders said later Monday that he would “assess” his path to victory following Tuesday’s contests.

Updated at 5:15 p.m.