Still thinking about the tax cut. Here's a wonky point: the TCJA was a fiscal stimulus -- very badly designed for that purpose, but it did throw money at (mostly rich) people. How would we expect the economics of such a stimulus to work? 1/
Stimulus is highly effective when the economy is depressed and interest rates are at the zero lower bound -- i.e., under the conditions Obama faced, when Rs pretended to care about deficits and forced spending cuts 2/
It should be much less effective when you're near full employment (which the Fed believes we are, which is what matters) and the Fed will raise rates to block overheating. In that case it will cause crowding out of other spending 3/
But here's the thing: crowding out takes time -- time for higher interest rates to drive the dollar up and reduce housing starts, time for the stronger dollar to worsen the trade deficit. And the post tax cut rise in $ and long-term rates didn't start until January 4/ 
Now, judging the tax cut by a couple of quarters' growth is stupid and/or disingenuous; but in any case we probably haven't seen the downside yet. The crowding out is still in the future 5/
