Trump is slated to attend his first meeting of NATO, the decades-long partnership that has become intrinsic to safeguarding the West but has been rattled by the new president's wavering on honoring its bonds. Trump has mused about pulling out of the pact because he believed other countries were not paying their fair share and he has so far refused to commit to abiding by Article 5, in which member nations vow to come to each other's defense. The president has recently shifted gears and has praised NATO's necessity while Secretary of State Rex Tillerson said Wednesday that "of course" the United States supports Article 5, though Trump still wants other nations to meet their obligation to spend 2 percent of their gross domestic product on defense. [...] putting some meat on the pledge, the leaders will agree to prepare action plans by the end of the year, plotting how to reach 2 percent over the next seven years, and show how they will use the money and contribute troops to NATO operations. European leaders have been particularly unnerved by Trump's reticence about NATO due to renewed aggression by Russia, which seized Crimea from the Ukraine in 2014 and, intelligence officials believe, interfered in last year's American elections. While in Belgium, Trump will unveil a memorial to the terrorist attacks of Sept.