It's an inexact science, but estimates tend to suggest that each additional 1 percent of annualized GDP growth will yield the U.S. Treasury an additional $400 billion in revenue in a given year. That's what static analysts miss when they scream that tax rate cuts will cost the government money. If they're pro-growth tax cuts, that need not be the case at all.
Democrats pretend not to believe this, but all throughout the Obama Administration, annual budget proposals made assumptions about the rate of economic growth, and assumed that revenues would be impacted by the rate of growth. The truth is that they know it's true but they pretend otherwise in order to argue that lower marginal tax rates will be the end of society.