points announcer: this is nbc nightly news with lester holt good evening, everyone president biden setting the stage for his face-to-face with russia s vladimir putin later this week, warning tonight the u.s. will respond if russia does not change its behavior the president with a stronger hand to play going into that meeting after cementing the fractured american bond with nato, meeting with fellow nato ministers in brussels today president biden declaring the military alliance and its core foundation of mutual defense are rock solid. as he works to nurture a relationship derided by president trump when he was in office. the president along with the rest of the world getting what may prove to be a preview of the summit. as we hear more today from president putin in an nbc news exclusive interview. but let s begin in brussels now with nbc s peter alexander. reporter: tonight less than 48 hours ahead of that high-stakes summit with russian president