While meeting with Baltic leaders in Latvia today, Vice President Joe Biden told them not to take some of Donald Trump 's comments about the North Atlantic Treaty Organization seriously, saying he doesn't believe the Republican presidential nominee fully understands the organization's mission."The fact that you occasionally hear something from a presidential candidate in the other party, it's nothing that should be taken seriously because I don't think he understands what Article 5 is," he said, referring to NATO 's founding principle of collective defense.The alliance was chartered in 1949 to provide Western Europe and the United States with a bulwark against the Soviet Union.In a July interview with The New York Times, Trump said he would make the United States' commitment to defense of other NATO allies contingent on those allies making adequate contributions to the alliance."We're talking about countries that are doing very well. Then yes, I would be absolutely prepared to tell those countries, 'Congratulations, you will be defending yourself,'" he told the Times.In a March appearance on ABC News' "This Week," Trump suggested the organization was "obsolete" because it was focused on Russia, not terrorism."I think NATO's obsolete. NATO was done at a time you had the Soviet Union, which was obviously larger, much larger than Russia is today. I'm not saying Russia's not a threat. But we have other threats. We have the threat of terrorism and NATO doesn't discuss terrorism, NATO's not meant for terrorism," he said.Trump walked back that comment in August, saying NATO had since formed "a new division focused on terror threats," but the nonpartisan website PolitiFact said he had actually been referring to a relatively minor intelligence-sharing policy change, and that there was "no evidence" that his comments had spurred the shift.