 NPR's Mara Liason reports. Another handful of House Democrats told their leaders that Biden should step aside, and more are expected to join them as Congress gets back to Washington this week. The president will hold a rare solo press conference during the visit of NATO leaders to Washington. It's part of an effort to show that in an unscripted situation without a teleprompter, he has the mental fitness to run and win and govern. And on Friday, the president will hold rallies in Michigan, another key swing state.