Tax RATE cuts increase tax REVENUE. See Harding, Kennedy and Reagan and the revenues in the years following the cuts.
If they believed in dynamic scoring and the past effects of tax simplification with rate cuts, their demand for “revenue neutral” would give them a license for MORE SPENDING.
I am just as happy to see them demand spending cuts on the assumption that revenues will not increase. Unfortunately, I don’t think Mitch has any intention of allowing spending cuts. This is just a way to prevent tax reform and keep the slush fund pork barrel spending Mitch loves so well.