 John Kirby tells ABC's Good Morning America that Ukraine is high on the agenda for this week's NATO summit, as well as improving the deterrence and defense capabilities of the alliance. Asked about concerns among NATO officials about the president being up to the job and how he'll reassure them, Kirby said. The fact that this summit is happening here in Washington, that these leaders are coming, says a lot about how much they value American leadership on the world stage and how much they respect and are grateful for the return of that leadership that President Biden has ushered in in the last three and a half years.