Anonymous Democratic senator says everyone's known for years Biden has mental lapses

Anonymous Democratic lawmakers admitted that President Biden has long shown signs of cognitive decline in their interactions with him, as Biden faces increasing pressure to drop out of the race following his shaky debate performance.

"The country saw [at the debate] what those of us who have had personal interactions with him have all known for the last 2½ years," one Democratic senator told NBC News.

Biden's halting performance at the debate last week reinforced concerns about his age and fitness for office that have been growing for months. The Biden campaign has been working damage control with major donors this past week, as political allies, high-profile donors, media pundits and editorial boards demand he step down.

Another Democratic lawmaker told NBC News that as many as 40 Democratic lawmakers have been texting one another since the debate, each one believing it's time for the president to bow out.

Biden has resisted these calls thus far, telling a supporter at the White House July 4 celebration on Thursday that he's "not going anywhere."

White House press secretary Karine Jean-Pierre also faced an onslaught of questions about Biden's fitness for office at Wednesday's press briefing. She said the administration has been "transparent" about Biden's health and dismissed the debate as a "bad night."

However, anonymous Democratic lawmakers in the NBC report said the president's debate performance wasn't a one-off and was consistent with concerning behavior they've seen throughout his term.