Lower tax rates mean higher revenues.
It works : see JFK and RWR
Of course this cannot work when applied to the extreme case of reducing the tax rate to zero. Therefore the best you can claim is that the tax rate that produces the highest revenue is somewhere below the the tax rates we have now. That is a claim that cannot be argued on general principles, but must be argued in the details. So let’s look at some details.
The history of the income tax rates is complicated by the fact that there are numerous rates and brackets, all of which could be said to comprise the “tax rate” in general. But let’s just pick one benchmark - the marginal tax rate of the highest bracket. Here is what has happened over the years:
1980: top rate was 70%
1982: top rate reduced to 50% (Reagan)
1987: top rate reduced to 38.5% (Reagan)
1988: top rate reduced to 28% (Reagan)
1991: top rate increased to 31%
1993: top rate increased to 39.6%
2008: top rate slightly reduced to 35%
2013: top rate slightly increased to 39.6% where it stands today.
Now compare this with the tax revenue over time as shown in the attached graph, shown revenue in trillions. (Data from OMB, Table 1.1—Summary of Receipts, Outlays, and Surpluses or Deficits (-): 1789–2018)
So while the revenue did increase during the Reagan years when the top income tax rate was cut dramatically, they also increased even more dramatically in the years that followed the Reagan cuts when the top rate was gradually raised (although never back to the highs of the pre-Reagan years). So it is hard to make the case that now, with the top rate at a relatively low 39.6%, that rates should be cut now to increase revenue. In any case, the burden is on those who claim the correlation to demonstrate it. I have at least cast doubt on that correlation.