U.S. President Joe Biden once again reassured countries on NATO's eastern flank, all of which used to be under the thumb of the former Soviet Union, that the Western defense alliance would help them in the event of an attack. "Article Five is a sacred commitment the United States has made. We will defend literally every inch of NATO -- every inch of NATO," the U.S. president said at a meeting in Warsaw on February 22 with attendees from the countries of the Bucharest Nine grouping, comprising Poland, Romania, Bulgaria, Hungary, the Czech Republic, Slovakia, and the three Baltic states Estonia, Latvia and Lithuania.