The vice president, long a skeptic of US military intervention, is the rare figure in the administration who can appeal to both the realist and hawkish wings of the GOP.

Tensions between the U.S. and its NATO allies have cooled off since most of the alliance's member states agreed to increase their defense spending from 2 percent of GDP to 5 percent by 2035, which many Trump supporters say is proof that his hard-charging negotiating tactics, even among friends, produces results.

Missouri Gov. Mike Kehoe signed a bill Wednesday that prohibits foreign money from funding ballot issue campaigns, making it the ninth state to enact such legislation.