By Kevin Liptak and Jeff Zeleny

Two weeks before becoming president, Joe Biden watched the January 6 attack on television from his home in Delaware, horrified as the unspeakable images of the insurrection unfolded and aghast at the sitting President's unwillingness to condemn it.

A year later, he marked that day with a speech that put into stark terms what the event meant for a nation still deeply split over its significance -- and excoriating his predecessor for his role in eroding American democracy.

In his speech from the Capitol's Statuary Hall on Thursday, the President wielded the sharpest language he's ever used about the attempted coup, denouncing "the former President" 16 times for lying about the election because he couldn't reck- on with losing.

"He's not just a former President," Biden said in his forceful remarks, "he's a defeated former President."

Biden touched upon his deeply personal views of the assault on democracy and the attack on the hallowed Capitol building where he spent nearly four decades during his time as a senator.

But he also acknowledged it wasn't a battle he necessarily expected or sought.

"I did not seek this fight, brought to this Capitol one year ago today," he said. "But I will not shrink from it either. I will stand in this breach, I will defend this nation, I will allow no one to place a dagger at the throat of democracy."

Biden worked over the holidays to write and refine an address that was bluntly honest about the motivations and consequences of the riot, along with the threats to American democracy that still persist. It's a topic that drives Biden, according to officials, but one that hasn't played a central role in his public agenda. He has left investigating the riot to Congress and made clear he won't interject into the Justice Department's prosecution of its perpetrators.

Still, the January 6 riot has doggedly shadowed Biden's first year in office. The insurrection was unsuccessful in pre- venting him from becoming president, but it has instead become a persistent reminder of the divisions he once promised to heal and the fraught political environment in which he governs.

Biden has made attempts to bridge those divisions by doing what he can to move on. Even as many Democrats warn of troubling steps taken around the country that could potentially undermine future elections -- including installing loyalists to Donald Trump on election boards and changing local voting laws -- the President spent his first year in office prioritizing other legislative battles, including Covid relief money, an infrastructure bill and a large social and climate spending package that is still pending.

Mindful of not allowing Trump to hijack his presidency, Biden has made it a habit not to mention his predecessor by name, though he still does sometimes. He recently claimed, "I don't think about the former President."

Yet Trump's influence has persisted, including in Congress where January 6 has become an enduring test of loyalty to the former President. While Trump canceled a news conference scheduled for Thursday at his Mar-a-Lago resort in Florida, he continues to spread false information about the election at rallies and during media appearances.

Trump's false claims about the election and the riot continue to undermine Biden among Republicans around the country. This week, an NPR/Ipsos poll found two-thirds of Republicans agree that fraud helped Biden win -- a claim that has repeatedly been discredited.