I think you're being fooled. Republicans cut the taxes on the wealthy markedly and leave to the Democrats to try to pay the bills:
The above is a chart which doesn't mean what many think it does.
As someone with a lot of experience paying income taxes over many decades,
one thing I've learned is that nominal marginal tax rates (from tax tables), & the
actual marginal tax rates can be greatly different. The tax tables make up only
a few of the over 100,000 pages of the tax code. Along with rate changes, the
fed also changed allowable tax avoidance mechanisms. When the nominal
rates were higher, there were generous things like accelerated depreciation
without recapture upon sale. In my experience the actual rates didn't change
much for those who play the game.
Btw, I favor lower marginal rates, & getting rid of tax avoidance schemes.
It makes for better economic incentives, it's fairer, it removes the advantage conferred
upon sophisticated tax dodgers, & it saves us money wasted on accounting tricks.