Many R senators and representatives have already postponed retirement many times because of Obama and the "unelectability" of Trump. Their reasoning for going now is as follows: Ds might take one or both houses of congress simply due to mid-course corrections in 2018. Even 4-5% GDP growth may not be enough to keep both houses in a midterm election anyway. The counter-argument is that NY, CA and IL are already showing increased stress due to the tax bill and the withholding schedules haven't gone out yet but bonuses and wage increases from private industries have. So, I am arguing that the professionals have got it wrong.