Biden strikes a contrast with Trump, offering a choice between ‘revenge’ and ‘decency.’

President Biden used his State of the Union address on Thursday to launch a series of fiery attacks against former President Donald Trump, a competitor whom he did not mention by name but made clear was a dire threat to American democracy and stability in the world.

In a televised speech to a joint session of Congress, Mr. Biden brought the energy his allies and aides had hoped he would display to warn of what could happen should Ukraine continue to lose ground to Russia. Invoking an overseas war at the top of his address was an unusual introduction to a speech that was in many ways a political argument for his re-election.

“Not since President Lincoln and the Civil War have freedom and democracy been under assault at home as they are today,” Mr. Biden said, raising his voice to a shout. “What makes our moment rare is the freedom of democracy, under attack both at home and overseas.”

Mr. Biden’s speech had to accomplish several goals at once, including taking credit for an economy that has outperformed expectations but whose effects many Americans say they cannot feel. In a speech that ran for an over hour, he ran through a lengthy list of issues, including immigration, abortion, prescription drug costs and the war in Gaza.

He also engaged in a back-and-forth with congressional Republicans, picking up a button circulated by Republicans that called for people to say the name of Laken Riley, a Georgia nursing student who was killed in February.

The authorities have charged a Venezuelan migrant, who crossed into the United States illegally and was then released on parole, in the case.