 Live from NPR News in Washington, I'm Jack Spear. Even as President Biden's ability to run for re-election is in the spotlight, the president continues to stumble publicly. Speaking at the NATO summit tonight, President Biden briefly called Ukrainian leader Volodymyr Zelenskyy Putin before correcting himself, but that gaffe is minor compared to the challenge Biden faces tonight, a one-on-one press conference. NPR's Windsor Johnston reports.