U.S. President Donald Trump and his NATO counterparts are due to gather Tuesday for a summit that could unite the world's biggest security organization around a new defense spending pledge or widen divisions among the 32 allies.
Just a week ago, things had seemed rosy. NATO Secretary-General Mark Rutte was optimistic the European members and Canada would commit to invest at least as much of their economic growth on defense as the United States does for the first time.
