Myth on the Right: The Bush tax cuts caused revenues to go up.
Republican spokespeople and other tax-cut enthusiasts have asserted that the tax cuts passed in 2001 and 2003 actually increased revenue. They often point to rising revenues from 2004 through 2007 following the tax cuts in May 2003. Unfortunately, as any Economics 101 student will tell you, correlation doesn't prove causation. Yes, revenue did rise, but we have to answer the question: Would it have risen anyway?
We can never be absolutely sure how the economy would have reacted if the tax cut legislation had failed for some reason in 2001 and 2003, but the consensus among experts is that the economy would have grown in the mid-2000s with or without the Bush tax cuts. That doesn't mean the tax cuts had no feedback effect at all—people reported more taxable income than they would have—but those beneficial effects were not so great that the tax cuts could have "paid for themselves."
The most damaging result of this myth is that Republican lawmakers feel less pressure to propose spending cuts. Why bother when cutting a tax rate will raise more revenue?