Closing Night at the D.N.C.: Joe Biden Accepts Democratic Nomination

The overarching focus of the party, however, was on defining Mr. Trump as an enemy of public health, economic prosperity and democracy itself. More than any other modern political convention, this one placed the greatest threat to Americans’ lives and freedoms not in a foreign capital or a terrorist encampment, or in the executive suite of an insurance company or a Wall Street bank — but rather in the Oval Office, and in the person of the incumbent president.

“This,” Mr. Biden said, “is a life-changing election. This will determine what America’s going to look like for a long, long time.”

If Democrats depicted Mr. Trump as an aspiring autocrat, then in their telling Mr. Biden took on the role of a sturdy holdover from an earlier government — a chairman of Senate committees, a shaper of laws and a counselor to presidents who was capable of delivering the practical prize of national stability if not a more romantic version of national salvation.

For Mr. Biden, his speech on Thursday night, at a Wilmington event center, was the culmination of nearly five decades in national politics, a career he began in his 20s as a Senate candidate who won a November 1972 election several weeks before he reached the constitutional age of eligibility to serve. After 36 years and two unsuccessful presidential campaigns, Mr. Biden finally achieved national office in 2008 as a political sidekick — Barack Obama’s running mate.

A child of Scranton, Pa., and Claymont, Del., Mr. Biden has long emphasized his family’s blue-collar roots in courting a multiracial coalition of working-class voters, as well as more affluent white moderates. In the Senate, he spent decades forging his credentials as an expert on foreign policy and the judiciary, along the way developing a reverence for Washington institutions and old-school Capitol Hill deal making.

Should Mr. Biden win in November, he would be the country’s second Catholic president, after John F. Kennedy. He would also be the first since Ronald Reagan not to hold an Ivy League degree.