The Republicans in Congress are going to be concerned about the 2018 elections. They want to keep the majority control in the House and Senate.  To retain the majority they will be concerned with how the voters appear to be accepting or disliking what Trump does. Unhappy voters who would voted out an incumbency get more favorable actions than voters who are complacent.  Mr Twitter has not faced Congress's ability to control him on many issues. And Donald can not fire Congress even though he claims he will.