Should Bernie Sanders emerge a big winner in Iowa’s Democratic presidential caucuses Monday night, sources who know Barack Obama told Newsmax that the former president is almost sure to issue a warning that another Democrat must be nominated in order to defeat Donald Trump.

The same sources say that an Obama warning about the Vermont senator would be a natural follow-up to recent anti-Sanders salvos from Hillary Clinton.

On Friday, during an interview for a podcast, the 2016 Democratic presidential nominee denounced the behavior of Sanders’ supporters as “distressing” and suggested it cost her the fall race against Trump.

“All the way up until the end, a lot of people highly identified with his campaign were urging people to vote third party, urging people not to vote,” Clinton said in an interview for the podcast “Your Primary Playlist.”

As to whether it cost her the close contest with Trump, Clinton told interviewer Emily Tisch Sussman: “It had an impact.”

Without mentioning Sanders by name, our sources said, the 44th president is expected to call for nomination of a candidate who appeals to Republicans and independents disappointed with Trump and can work with Republicans in Congress.

[The latter is a not-so-subtle follow-up to an earlier Clinton interview in which she said of serving with Sanders in the Senate: “Nobody likes him, nobody wants to work with him, he got nothing done.”]

“If Bernie wins comfortably—I’m talking in the 30-something percentages—there will be a collective freak-out among the Democratic political establishment,” predicted one veteran caucusgoer in Des Moines who requested anonymity, “You’ll see Obama come out for ‘Anybody but Bernie’ and a lot of others will as well.”

There is disagreement among some Democrats about Obama taking on Sanders. Bill Press, author and TV commentator and former California Democratic chairman, told Newsmax: “Even if Sanders wins Iowa, I don’t think President Obama will jump in by endorsing another candidate or warning about Bernie. I don’t think he’d want to risk angering devoted Bernie supporters Democrats will need, no matter who the nominee is, in November.

Press also pointed out that Obama “knows the Iowa caucuses don’t really mean that much. Nevada and South Carolina are much more significant.”

There is precedent for what an Obama statement critical of a front-runner presidential hopeful. On July 2, 1960, former President Harry Truman made a televised statement calling on Massachusetts Sen. and front-running presidential candidate John F. Kennedy (“Joseph F. Kennedy” is how he referred to him, an apparent slip up in using the first name of the senator’s multi-millionaire father) to “step aside” from the nomination contest.

In a reference to Kennedy’s youth, Truman called for a nominee with “maturity and experience” and also took shots at the senator’s “overzealous backers” and wealth (he warned that the Democrats should not become the “party of privilege.” (In a subsequent statement, JFK graciously praised Truman’s service but made it clear he wasn’t standing down).

Whether Obama will speak out about Sanders and how Sanders will respond if he wins big in Iowa is sure to be one of the most intriguing political developments of the Democratic nomination battle.

John Gizzi is chief political columnist and White House correspondent for Newsmax. For more of his reports, Go Here Now.