Call it the "Seriousness Test." Any so-called deficit hawk that refuses to countenance increasing federal taxes simply isn't serious. After all, as the CBO concluded in January, with tax revenues now below 15%, "levels that low have not been seen since 1950." The two-year tax cut compromise in December made matters worse, adding $400 billion to the deficit this year and next. And measured as a percentage of GDP, corporate profits are near their highest point in the last thirty years, while corporate tax revenue is at its lowest since Truman was in the White House.
Nevertheless, as Tuesday's glowing Washington Post profile of the Senate's "Gang of Six" deficit cutters made clear, for Republicans everything is on the table - except, that is, raising taxes.

Like the Bowles-Simpson deficit commission established by President Obama, the bipartisan group is nearing a proposal to "cut the federal budget deficit by $4 trillion over 10 years, roughly four times the savings the White House proposed in February." Virginian Mark Warner, its Democratic ring-leader warned of fiscal ruin "unless Congress and the White House come together in support of highly unpopular measures such as raising taxes and overhauling Social Security and Medicare." His Republican counterpart, Saxby Chambliss (R-GA), agreed that "Everything is on the table."
Well, not quite everything.
As the Washington Post reported, the GOP remains handcuffed by its ideological blinders and its anti-tax enforcer, Grover Norquist:

The initiative has also attracted fierce critics, including Grover Norquist, a Republican anti-tax strategist who publicly accused Chambliss, Coburn and Crapo of abandoning their pledge not to raise taxes by lending support to the notion that the government could increase total tax revenue by closing loopholes and lowering income tax rates.
The three just as publicly dismissed the charge.
"None of us have ever voted for a tax increase, and I don't intend to," Chambliss said Monday. But the tax system is "way out of kilter," producing $1.1 trillion in revenue in 2009 while giving away $1.6 trillion in deductions and other breaks, he added. "We can do it in a fair and reasonable way and...actually lower rates and at the same time raise revenues."

Of course, one fair way to raise revenues would be to simply raise upper-income tax rates to at least their Clinton-era levels, when the wealthy and not-so-wealthy alike enjoyed a booming economy.
Consider the graph above of U.S. tax revenue and spending as reflected in President Obama's proposed $3.7 trillion budget for fiscal year 2012. In one sense, it looks exactly as you'd expect. The combination of the Treasury-draining Bush tax cuts and crippling Bush recession sent tax revenues as a percentage of GDP to its lowest point since 1950. Meanwhile, the cost of the two unfunded wars and badly needed funding to boost demand during the current recession sent spending temporarily well above its historical 18% to 22% range. With the stimulus nearing its end and the conflicts in Iraq and Afghanistan winding down, federal spending will begin coming down.
But the chart also highlights the fraud of Republican mythology which pretends that tax cuts pay for themselves. As a percentage of the American economy, tax revenues peaked in 2000; that is, before the Bush tax cuts of 2001 and 2003. Despite President Bush's bogus claim that "You cut taxes and the tax revenues increase," Uncle Sam's cash flow from individual income taxes did not return to its pre-dot com bust level until 2006. (Past analyses from the Center on Budget and Policies Priorities revealed that the Bush tax cuts accounted for half of the deficits during his tenure, and if made permanent, would add more to the national debt than Iraq, Afghanistan, the stimulus and TARP - combined.)

Corporate tax revenue plummeted during the Bush recession, but is forecast to begin recovering along with the overall economy. While President Obama, the Bowles-Simpson Commission and the Gang of Six have all called for lowering U.S. corporate rates while ending the pervasive loopholes that let major companies and entire sectors escape all or most of the tax bite, many Republicans have called for eliminating it altogether. And that, as Matthew Yglesias helpfully explained, is just nuts:

There's no particularly compelling reason to want corporate income tax revenue to be a large share of GDP, but the point highlighted here is that in a climate where the country needs more tax revenue in the medium-term, there's no reason corporate income tax reform should be strictly revenue neutral. The headline rates are so high, and yet the loopholes are so ubiquitous, that it's very easy to design reforms that are both clearly pro-growth and revenue-enhancing, even apart from the fact that deficit reduction (at the right time) can be growth-enhancing.

Ultimately, increasing tax revenue is just one part of getting the $14 trillion national debt under control. Since 2001, American defense spending in dollar terms has doubled; as percentage of GDP, it jumped from 3% to 5%. (It is worth noting that while George W. Bush was the first modern president to cut taxes during wartime, the final tab from Iraq and Afghanistan could reach $3 trillion.) And while Social Security is not a driver of deficits (and can be improved further by raising the income cap on payroll contributions to, say, $250,000), health care is. (As Ezra Klein put it, "The problem is not MedicareandMedicaid. It's health care." And as Paul Krugman explained, the cure for that problem isn't without pain.)
But at the end of the day, when it comes to cutting deficits and reducing the U.S. national debt, you can't there from here without raising taxes. When the effects of this recession (and perhaps, the 2012 presidential election) are over, that's precisely what we should do.
Recent history reminds us that it can be done. After all, the last time the top tax rate was 39.6% during the Clinton administration, the United States enjoyed rising incomes, 23 million jobs and budget surpluses. More important, the American tax burden hasn't been this low in generations. Thanks to the combination of the Bush Recession and the latest Obama tax cuts, the AP reported, "as a share of the nation's economy, Uncle Sam's take this year will be the lowest since 1950, when the Korean War was just getting under way." In January, the Congressional Budget Office (CBO) explained that "revenues would be just under 15 percent of GDP; levels that low have not been seen since 1950." That finding echoed an earlier analysis from the Bureau of Economic Analysis. Last April, the Center on Budget and Policy Priorities concluded, "Middle-income Americans are now paying federal taxes at or near historically low levels, according to the latest available data." As USA Today reported last May, the BEA data debunked yet another right-wing myth:

Federal, state and local taxes -- including income, property, sales and other taxes -- consumed 9.2% of all personal income in 2009, the lowest rate since 1950, the Bureau of Economic Analysis reports. That rate is far below the historic average of 12% for the last half-century. The overall tax burden hit bottom in December at 8.8% of income before rising slightly in the first three months of 2010.
"The idea that taxes are high right now is pretty much nuts," says Michael Ettlinger, head of economic policy at the liberal Center for American Progress.

Or, as Bill Clinton might put it: it's the tax revenue, stupid.
(For more background, see the historical tables of the Office of Management Budget).