WASHINGTON—The three-country coalition that launched airstrikes in Syria came together despite persistent trans-Atlantic tensions—a period of unity made possible, White House officials said, because of good relations between the U.S. and French presidents and an alliance against Russia that eased strains with the U.K.
The coalition was rooted in the shared goal of ending the use of chemical weapons in Syria. French President Emmanuel Macron was the first of the three countries’ leaders to lean publicly in to a military response...