Turkey had long planned to root out the militia, the Syrian Democratic Forces, which it considers a terrorist organization. President Trump gave Turkey a green light on Sunday, sparking fierce debates in the U.S.

Mr. Trump called the Turkish operation “a bad idea” but reiterated his opposition to “endless, senseless wars,” even as leading Republicans expressed outrage and said the offensive could inflict damage on Washington’s relationship with Turkey, a NATO ally , and open a new front in Syria’s eight-year-old war.

Go deeper: U.S. and Turkish officials say President Recep Tayyip Erdogan of Turkey has repeatedly guided Mr. Trump toward positions that are at odds with those of Mr. Trump’s own national security advisers and Republican allies.

China-Hong Kong divide ensnares more multinationals

The video game company Activision Blizzard is the latest U.S. firm to be caught in the crossfire between China’s government and Hong Kong’s pro-democracy supporters, and Apple has become a target of Chinese state media.