 Ukraine's defense against Putin's invaders to figure prominently at the NATO summit opening this week in Washington. At the summit, the U.S. is expected to announce new steps to strengthen Ukraine's air defenses and military capabilities. And there will be significant announcements on increasing NATO's military, political and financial support for Ukraine. On the sidelines of the summit, President Biden will host an event with Ukraine's President Volodymyr Zelensky, along with other NATO leaders. ABC's Perry Russom, the summit running Tuesday through Thursday of this week.