Which European country should lead efforts to support Ukraine against Russian aggression?

French President Emanuel Macron has led Europe's efforts to support Ukraine against Russian aggression.  But with his term running out, and unrest at home, Europe will need to find a new head of state to lead national security efforts in Europe.  NPR Pentagon Correspondent Tom Bowman breaks down which country could be best poised to take the lead with Sources & Methods host Scott Detrow.