On the R Street Institute Blog, Kevin Boyd writes:
“We’re not considering any boots-on-the-ground approach,” then-President Barack Obama said during an Aug. 30, 2013 news conference about the situation in Syria. The former president would repeat his promise not to deploy “boots on the ground” over the next few years. But by 2016, U.S. ground forces were operating in Syria as part of the war against Islamic State.
"President Donald Trump now plans to expand the war against ISIS. U.S. Marines have deployed alongside Syrian rebels as they plan an assault on the ISIS capital of Raqqa and expect to provide artillery support for the upcoming offensive. Before U.S. Marines engage in ground combat against the enemy, it’s time for a debate about the mission against ISIS. When Obama first ordered U.S. military action against ISIS in the summer of 2014, he did so without congressional approval.
"The U.S. Constitution gives Congress alone the power to declare war, although the reality has always been more complicated than that...."