Macro-economists don’t know squat. From The Zman at theburningplatform.com:
Way back in the early days of the conservative movement, it was assumed that Federal spending was both unsustainable and damaging to the country. Cutting the size and scope of government was their thing. The tool they eventually settled on to reduce Federal spending was taxes. If they made high taxes so unpopular with the public, the Left could not keep raising taxes. If they could not raise taxes to cover their spending, they would eventually have to yield to the mathematics.
Obviously, that never happened. The big tax reforms of the 1980’s did simplify taxes and lower rates on rich people, but revenues remained stable. At the same time, spending kept growing. One of the unspoken truths of fiscal policy is the percent of GDP that is consumed by Federal taxes does not change much of time. The range is between 15% to 18%, depending on when tax policy was changed. This is the logic of the flat tax. One rate, no deductions and no more IRS.
Spending, of course, keeps going up, no matter who is in office. Despite their rhetoric, the Republicans are the big spenders. In the 1980’s they had to spend on the military to win the Cold War. In the Bush years it was the crusades against Islam. It is only when a Democrat is in the White House that the Republicans get tight-fisted, and even that is mostly ceremonial, as we have seen with the last Covid bill. It turns out that there is no relationship between taxes and spending.