Trump declines to endorse NATO's Article 5

In deference to President Trump, NATO leaders agreed not to focus on Russia during this week's summit. At today's opening session, they hoped he'd endorse the Alliance's Article 5 -- the principal that "an attack on one member nation is an attack on all.” Instead, he lectured about defense spending and "fairness" to the United States, even though the only time NATO's ever invoked Article 5 was after September 11. What are the consequences for Europe's trust in America as the leader of the free world since World War II?