President Biden during his State of the Union address Thursday defended a failed bipartisan border bill, snapped back at hecklers and called out former President Trump for saying migrants "poison the blood of our country."

Why it matters: Biden went on offense on one of his most vulnerable political issues — and Republicans' favorite line of attack.

• "We can fight about the border — or we can fix it. I'm ready to fix it. Send me the border bill now," Biden said during his Thursday night address.

What they're saying: During his remarks, Rep. Marjorie Taylor Greene (R-Ga.) shouted the name of a Georgia nursing student killed by an undocumented immigrant, Laken Riley.

• Biden responded, referring to Riley as "an innocent young woman who was killed by an illegal."
• He held up a pin given to him by Greene as he entered the chamber, and then addressed Riley's parents.
• "My heart goes out to you, having lost children myself," he said.

Zoom in: The president repeatedly referenced Trump — denouncing the former president for demonizing immigrants and taking action to derail a bipartisan border bill.

• "I'm told my predecessor called Republicans in Congress and demanded they block the bill," Biden said. "He feels it would be a political win for me — and a political loser for him.
• "And if my predecessor is watching, instead of playing politics, pressuring members of Congress to block the bill, join me in telling the Congress to pass it," he added.
• "I will not demonize immigrants — saying they 'poison the blood of our country' — as he said in his own words."

Biden defended a bipartisan border deal that met a swift failure in the Senate because of objection by Republicans, egged on by Trump.

• He shot back at hecklers, saying to "look at the facts" after he touted the bill's support from the Border Patrol union.

Between the lines: Biden and Democrats have struggled to find a winning message on immigration and the border. The failures of the bipartisan border deal has given them an oppening to go on attack.

• Polls have repeatedly shown immigration to be one of the top concerns for American voters.

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