Turkey’s powerful military has massed troops and heavy weapons on its border with Syria, as U.S. troops heeded President Trump’s order to step aside while Turkish troops prepare an offensive against Kurdish-led Syrian Democratic Forces. Trump’s abrupt decision to abandon the U.S.'s Kurdish allies in Syria came after a phone call on Sunday with Turkey's authoritarian president, Recep Tayyip Erdogan. Trump insisted he’d won assurances that Turkey would limit the scope of its fight against Kurdish forces, tweeting, “if Turkey does anything that I, in my great and unmatched wisdom, consider to be off limits, I will totally destroy and obliterate the Economy of Turkey.” Trump’s move drew condemnation on both sides of Washington’s political divide. Republican Senator Lindsey Graham, a close Trump ally, called the withdrawal “shortsighted and irresponsible.” Democratic House Speaker Nancy Pelosi called it “a deeply disturbing development.”