Biden delivers remarks at NATO summit in Washington, D.C.

President Joe Biden faces a pivotal moment this week as he prepares to host the leaders of more than 31 nations in Washington with a sudden new mission: command the world stage and stabilize a reelection campaign in crisis.

Much was already riding on Biden's performance at the summit marking the 75th anniversary of the NATO alliance. While his election opponent, former President Donald Trump, has questioned America's role in the organization, Biden has sought to reaffirm the U.S. commitment to NATO.

Yet after Biden's dismal debate performance 11 days ago, he must now allay the fears of worried Democrats openly discussing whether he should drop out of the race or remain their party's presidential nominee. Biden is under immense pressure to calm his critics by demonstrating competence and coherence as he welcomes NATO allies and partners to Washington for the three-day summit and as he tries to prove his case against Trump.