Follow for live updates on Super Tuesday as voters in more than a dozen states head to the polls.

President Biden’s advisers are eager for the coming general-election fight and counting on voters to start paying more attention to Donald J. Trump, with the president himself even proposing and dashing off videos to ridicule the things his Republican rival says.

Mr. Trump is relishing the chance to contrast himself with Mr. Biden, as he did along the Texas-Mexico border last week, and trusting that Mr. Biden has the tougher job: convincing voters that their views of how the country is doing are wrong.

With the former president expected to rack up big wins on Super Tuesday and Mr. Biden preparing to deliver his State of the Union address on Thursday, this week is expected to clarify the coming choice for an American public that in many ways remains in disbelief that 2024 is headed toward a 2020 rematch.

The Supreme Court’s unanimous ruling on Monday keeping Mr. Trump on the ballot after some states sought to bar him for his role in the Jan. 6, 2021, attack on the Capitol kicked off a critical period that both campaigns see setting the tone and defining the early contours of the presidential campaign.

By most accounts, Mr. Biden begins behind.

A New York Times/Siena College survey over the weekend showed Mr. Trump ahead 48 percent to 43 percent among registered voters. Mr. Biden is hampered by widespread concerns about his age and his handling of the job, fractures in the Democratic coalition over Israel and a general sourness about the state of the nation.

But Mr. Biden also enters the expected general election contest with a number of key structural advantages, including a sizable financial edge and a lack of distractions on the scale of Mr. Trump’s four criminal trials.