The rise of the Tea Party five years ago may have among the most ironic developments in modern American political history. After all, the astro-turf protesters who chanted "Taxed Enough Already" on Tax Day 2009 had just received the largest two-year tax cut ever, courtesy of the same Obama stimulus package they wrongly maligned. And by the next year, total federal tax revenue as a share of the U.S. economy plummeted to 15 percent, the lowest level since the Korean War.
Five years later, Americans are still not taxed enough already (TEA) by Uncle Sam. Even with the economic recovery, higher rates on income and capital gains for upper-income Americans and the end of the temporary payroll tax holiday bringing in record revenues, federal taxes are still not covering what the Treasury needs for--and what Americans say they want from--the government.
Here's why.
As Jonathan Cohn documented, data from the Organization of Economic Cooperation and Development (OECD) show that "relative to other countries, tax rates in the U.S. are relatively low, even when you throw in local and state taxes and add them to federal levies." But even leaving international comparisons aside, effective federal tax rates are lower than they've been historically. In the Washington Post, Christopher Ingraham turned to the nonpartisan Congressional Budget Office (CBO) to show that "your taxes are really low, in one chart":

But Ingraham's chart actually understates how much lower the tax burden has become. If you go back to 1960, as the New York Times' David Leonhardt did two years ago, it's clear that effective tax rates have spiraled down, especially for the very, very rich:

That result should come as no surprise. The top marginal tax rate topped 90 percent when John F. Kennedy took the oath office. After one year of the Reagan Revolution, it was down to 28 percent. Even more important, capital gains rates remain below historical levels, creating (as the Washington Post reported back in 2011) perhaps the single greatest factor fueling America's record income inequality:

Leaving the income gap aside, Uncle Sam's annual take from all sources isn't big enough. According to the CBO, federal revenue as a percent of GDP will hover just above 18 percent for the next decade. While that is above the historical level of 17.4 percent dating back to 1974, it's well below the 20 percent level reached during the only five times Washington balanced its budget since 1969.

The spending side of the equation is just as important. Historically, Uncle Sam has spent the equivalent of 20.5 percent of GDP each year. Over the next five years, CBO reports, that figure will be 21.0 percent. Over the next decade, outlays will hit 21.5 percent (below Ronald Reagan's 1983 peak of 23 percent), but reflecting additional spending on Medicare, Social Security and interest on the national debt. In contrast, Paul Ryan's House GOP budget would spend only 18.1 percent.
The GOP's slash-and-burn budget isn't just well below the levels of the past four decades. With the federal deficit dropping again this year, it's certainly not necessary now. Oh, and one other thing. Americans don't want to cut government spending. In survey after survey, they identify only foreign aid, less than one percent of Uncle Sam's spending, as the one area they want cut. (Recent polling suggests that people are generally comfortable with the federal government's current tax bite.)
All of which means Americans need to generate more tax revenue, not less. Luckily, Americans are still not taxed enough already.