Quote Originally Posted by carl View Post
What happened is relevant. And after the tax rates were lowered, tax revenues went up.

In 1982, the top individual rate was lowered from 70% to 50%. Individual tax receipts were just under 300 billion in that year. In the years that followed, individual tax receipts climbed until they were right around 400 billion. That year the top rate was again lowered from 50% to 28% and individual tax receipts continued to climb until in 1990 they were around 450 billion.

In 2003, the top rate was lowered from 39.8% to 35%. No effect on individual receipts that year and the next but climbing receipts every year until 2007.
The problem with these formulations is that tax policy is only one among many variables. Just for example, in the 1970s the baby boom generation was in college, consuming much and producing little. In the 1980s they got jobs and started paying taxes. In the 1990s they started earning seriously and investing seriously. The movement of that demographic bulge into a fully productive role was not a function of tax policy, but it certainly had a large impact on government revenues.

In 2003 the country was moving from recession into recovery, a recovery that accelerated (for dubious reasons, but that's another issue) through 2008. The extent to which tax policy alone was responsible for either the recovery or the increase in revenues is highly debatable. As one factor among many, that period was characterized by extremely low interest rates, so it's hard to determine whether an increase in business activity was due to lower taxes or cheap money.

Assigning a causative role to a single variable in a complex system is always a questionable practice.