Biden speaking with supporters in Pennsylvania on Sunday.
President Joe Biden sent a letter to congressional Democrats on Monday.
  • Biden sent a stern letter to congressional Democrats reiterating that he has no plans to drop out.
  • He said questions about him were "well-aired for over a week," adding, "It's time for it to end."
  • The list of Democrats calling for Biden to drop out is likely to grow this week.

As lawmakers head back to Washington on Monday after their one-week recess, President Joe Biden is issuing a stern warning: I'm not going anywhere; time to pipe down.

In a letter to Democrats in both chambers, Biden struck a defiant tone, even as he acknowledged "good faith fears and worries about what is at stake in this election."