Biden and congressional Democrats are headed toward an all-out war

• This week is the most important yet for Biden's struggling candidacy.
• Democratic lawmakers are returning to DC, and more may go public about their concerns.
• Biden keeps insisting he won't go anywhere and is growing increasingly defiant.

President Joe Biden and congressional Democrats increasingly appear to be on a collision course.

As lawmakers return to the Capitol for votes this week, conversations among them about the president's future are going to ramp up.

Reporters are going to be asking any Democratic lawmaker in sight whether they believe Biden should remain their party's nominee against former President Donald Trump. Inevitably, some of them are likely to say that he should not, or that they continue to have grave concerns about his future.

As of Monday morning, five House Democrats have publicly called for Biden to step aside, while two have pointedly said that he can't win. In private, the situation seems more dire. According to several media reports, four more senior Democrats — including Reps. Jerry Nadler of New York, Mark Takano of California, Adam Smith of Washington, and Joe Morelle of New York — have privately said that Biden should drop out. Though no Democratic senator has publicly called for Biden to go, The Washington Post reported that the "consensus" among them is that he should, citing two Democratic senators. The Post also reported that Sen. Mark Warner of Virginia is among them.

With the dam teetering on the edge of breaking, Biden has remained defiant.

On Monday morning, he sent a letter to congressional Democrats — which his campaign was quick to make public — insisting that he's not going anywhere, saying that the "question of how to move forward has been well-aired for over a week now" and that "it's time for it to end."

Shortly thereafter, the president called into MSNBC's "Morning Joe," saying that if any of the "elites in the party" didn't want him to run, they should "challenge me at the convention."

That comes after days of Biden insisting that he's staying. On Friday, he told ABC's George Stephanopoulos that he would only drop out if "the Lord Almighty comes down and tells me" to do so.

All of this makes the week ahead extremely important for Biden and the Democratic Party.

At this point, the best possible outcome for Biden is that Democrats on Capitol Hill simply shut up and fall in line, and that the president continues barrelling into the November election with multiple Democrats having gone on record saying that he should have stepped aside.

The worst possible outcome for Biden is that a public consensus emerges among congressional Democrats that he must go, and that party leaders follow suit by issuing calls for him to drop out. Though Biden insisted that wouldn't happen during his Friday interview on ABC, it's difficult to see how he could shoulder on if it did.

Perhaps the most disastrous outcome for the Democratic Party is something in the middle: A large minority of House Democrats call for Biden to step aside, but he remains the nominee, irreparably damaged by the dissent within his own party.

It's that scenario that Rep. Ritchie Torres of New York alluded to in a statement Monday morning. He said that public speculation about Biden was "creating and compounding" the problem and that the "process by which we decide how to move forward matters as much as the decision itself."

"Regardless of where one stands on the question of President Biden's political future, the intra-party mixed messaging strikes me as deeply self-destructive," Torres said. "The drip, drip, drip of public statements of no confidence only serve to weaken a President who has been weakened not only by the debate but also by the debate about the debate."