President Donald Trump is in London, marking the 70th anniversary of NATO.
CNN spoke to James Townsend, a former deputy assistant secretary of defense for Europe and NATO, who said: "the betting is that there are going to be some fireworks."
The president has called the alliance "obsolete" and its members "delinquent" for not spending more on defense.
Later in the program, we also unpack the recent terror attack in London.
Two people are confirmed dead and three others were wounded in a "terror-related attack" over the weekend. ISIS has claimed the attack.
What do we know about the attacker's motives? How should we deal with those who might harm us, physically and psychologically?
Matthew Levitt, Senior fellow and director, Reinhard Program on Counterterrorism and Intelligence, The Washington Institute for Near East Policy; @Levitt_Matt
Frank Langfitt, Correspondent, NPR's London bureau; author, "The Shanghai Free Taxi: Journeys with the Hustlers and Rebels of the New China;" @franklangfitt