Biden called on Congress to send him a bipartisan national security bill amid Russia's ongoing war in Ukraine.

"If the United States walks away, it will put Ukraine at risk. Europe is at risk, the free world will be at risk," he said.

Biden also had a message for Russian President Vladimir Putin: "We will not walk away," he said to applause.

"We will not bow down! I will not bow down! In a literal sense, history is watching," Biden said.

Many Republicans have been increasingly skeptical of foreign aid to Ukraine versus spending on domestic priorities like the southern border. Biden and the GOP have not been able to agree on new immigration changes, despite a Biden-backed deal in the Senate.

Biden took his first jab at Trump of the night as he called on Congress to provide further assistance to Ukraine in its fight against Russian invaders.

"Ukraine aid is being blocked by those who want to walk away from our world leadership," he said. "It wasn't long ago, when a Republican president named Ronald Reagan thundered, 'Mr. Gorbachev, tear down this wall.'"

Biden continued, "Now, my predecessor, a former Republican president, tells Putin, 'Do whatever the hell you want.' That's a quote. The former president actually said that bowing down to a Russian leader. I think it's outrageous, it's dangerous and it's not acceptable."

Biden dubbed the current time an "unprecedent moment" in America, drawing parallels to his speech Thursday with that of former President Franklin Delano Roosevelt in 1941, right before the U.S. entered World War II.

"Tonight, I come to the same chamber to address the nation. Now, it's we who face an unprecedented moment in the history of the union. And yes, my purpose tonight is to wake up the Congress and alert the American people this is no ordinary moment either," Biden said.

The president warned that "freedom and democracy under assault" both "at home and overseas at the very same time," pushing for aid to Ukraine as it works to fight off Russia's invasion -- adding a warning as Congress proves unable to agree on a bill to send aid to Kyiv.

"If anybody in this room thinks Putin will stop at Ukraine, I assure you he will not," Biden said.

While Biden entered the U.S. Capitol House chambers for his State of the Union address, Secretary of Education Miguel Cardona was announced as the "designated survivor."

The designated survivor is a Cabinet member chosen to remain physically away from the president and vice president in case of an emergency or an attack during the State of the Union.

Cardona will go to an undisclosed location for the duration of the address.

Hi, I’m Monica Potts, a senior political reporter at 538. I’ll be watching the State of the Union and helping provide analysis and commentary about some of the themes from Biden’s speech. I’ll be especially interested in what he has to say about abortion, foreign policy, democracy and the economy. As my ABC News colleagues have noted, the night is really a sort of campaign kickoff event, and how he frames those issues could preview how he plans to talk about them with voters.

I’ll be able to provide context on how voters think about those issues as well. While my colleagues at 538 and I know that the State of the Union itself tends not to move the needle politically, the speech can tell us where Biden plans to focus his efforts this election year. It’s also an opportunity for Biden to assuage concerns from his own voters and inspire them to vote in November. The presidential race has the potential to be as close as the last two, so he’ll need it if he wants to win.

-Monica Potts, 538