Several European countries have deployed soldiers to Greenland after President Trump signaled he may seize the semiautonomous Danish territory by force. The deployment by France, Germany, Sweden, Norway, Finland, the Netherlands and the U.K. is largely symbolic, with only a few dozen personnel deployed alongside Danish forces for joint military exercises. Article 5 of NATO’s charter says that an armed attack against one member is considered an attack on all, but the charter does not specify a course of action if one NATO member attacks another.