Establishment conservatives love to talk about the need to cut government spending, but they always seem to find an excuse whenever there is a serious effort to actually do it.

Last year, for example, they opposed cutting Medicare as part of health care reform. Now they are banding together to stop cuts in defense spending, which is a fifth of the federal budget, even as they also insist that the deficit is our most critical problem.

This hypocrisy was on full display on Oct. 4, as American Enterprise Institute president Arthur Brooks, Heritage Foundation president Ed Feulner, and Weekly Standard editor Bill Kristol penned a joint op-ed for the right-wing Wall Street Journal editorial page on why the defense budget should be totally off limits to budget cutters.

First, they claim the military is not the “true source of our fiscal woes.” No one is saying the defense budget is the sole source of the deficit, but the fact is that it has risen from 3 percent of the gross domestic product in fiscal year 2001 to 4.7 percent this year. That additional 1.7 percent of GDP amounts to $250 billion in spending — almost 20 percent of this year’s budget deficit. And according to a recent Congressional Research Service report, the cost of wars in Iraq and Afghanistan alone accounted for 23 percent of the combined budget deficits between fiscal years 2003 and 2010.

Brooks, Feulner and Kristol then claim that “terrorism and piracy in sea lanes around the world,” potential future threats from a “nuclear Iran” or a China “that can deny access to U.S. ships or aircraft in the Asian-Pacific region” justify a defense budget only slightly smaller as a share of GDP than at the height of the Cold War, when the Soviet Union had thousands of nuclear missiles targeted directly at the United States.

Tufts University foreign policy expert Daniel Drezner was underwhelmed by the argument. “Terrorism and piracy are certainly security concerns — but they don’t compare to the Cold War,” he said. “A nuclear Iran is a major regional headache, but it’s not the Cold War. A generation from now, maybe China poses as serious threat as the Cold War Soviet Union. Maybe. That’s a generation away, however.”

American University defense expert Gordon Adams was equally unimpressed by the trio’s rationalization:

It is little more than a façade to justify growing defense budgets as far as the eye can see, affordable or not. First, we are leaving Iraq as we speak and will be drawing down in Afghanistan starting next year… [which] frees up a considerable amount of military personnel. Second, anyone who thinks terrorists and pirates justify a $700 billion defense budget and a 2-million-person force (actives and reserves) has clearly drunk way too much Kool-Aid. These missions are important, but they do not drive anywhere near that number of forces. Third, …The U.S. has ample sea and air power to cope for decades with a rising China, whose economic pursuits pose a much more significant problem for the U.S. than their military pursuits.

The fact of the matter is that China spends half the share of its GDP on defense as the U.S. — less than $100 billion last year, according to the Stockholm International Peace Research Institute, the primary source for internationally comparable data on military expenditures. That’s less than 15 percent of what we spent. According to SIPRI, the military budgets of every nation on earth other than the U.S added together would only come to 46 percent of the total. In other words, the U.S. defense budget is 54 percent of world military spending.

The idea that we need a defense budget almost 60 percent larger as a share of GDP than a decade ago is ludicrous. While it is true that the wars initiated by George W. Bush and a Republican Congress will impose a financial burden on American taxpayers for many years to come, that isn’t enough to justify spending more than half of the world’s military expenditures. Almost all our NATO allies get by spending well less than half what we spend as a share of GDP.

To their credit, many of the tea party candidates likely to be elected to Congress next month have made clear that Pentagon spending will be on the chopping block. Politico’s John Bresnahan recently quoted Tea Party Patriots leader Mark Meckler saying, “Everything is on the table. I have yet to hear anyone say, ‘We can’t touch defense spending,’ or any other issue ... Any tea partier who says something else lacks integrity.”

Tea partiers aren’t the only ones on the right taking aim at the defense budget. On May 18, Sen. Tom Coburn, Republican of Oklahoma, sent a letter to the National Commission on Fiscal Responsibility and Reform urging “due diligence on national defense spending.” He detailed a number of areas where savings could be achieved. Sen. Judd Gregg, Republican of New Hampshire and a member of the commission, agreed that the defense budget needs to be looked at and suggested another base-closing commission to cut unnecessary spending.

Defense Secretary Robert Gates, originally appointed to his position by George W. Bush, has taken the lead on finding $100 billion in savings over the next five years. But the magnitude of our budgetary problems requires much deeper cuts. And as a recent Congressional Budget Office briefing makes clear, deep cuts are impossible without scaling back our defense commitments.

As the painful process of deficit reduction moves forward next year, many conservatives are going to scream that our national security is being fatally undermined. They will need to be reminded that excessive national debt also undermines our national security — especially when much of it is owned by foreigners like the Chinese. As Secretary of State Hillary Clinton recently warned:

Our rising debt level poses a national security threat, and it poses a national security threat in two ways. It undermines our capacity to act in our own interests and it does constrain us where constraint may be undesirable. And it also sends a message of weakness internationally ... It is very troubling to me that we are losing the ability not only to chart our own destiny, but to have the leverage that comes from this enormously effective economic engine that has powered American values and interests over so many years.

The only real alternative to deep defense cuts would be to strengthen our nation’s revenue-raising capacity. Historically, wars have always been financed in large part by tax increases, as I detailed in a column in Forbes last year. It was a tragedy that Republicans chose to put the cost of Iraq and Afghanistan on the national credit card, rather than asking the American people to sacrifice a little bit. As it is, the only people who have sacrificed are our armed forces and their families.

It’s easy to see why Republicans wanted desperately to avoid asking Americans to sacrifice — they would almost certainly have demanded that we get out of Iraq and Afghanistan long before now. According to a September New York Times/CBS News poll, 71 percent of Americans think the war in Iraq wasn’t worth it. That number would unquestionably be higher if taxes had been raised as a consequence.

As the great economist Adam Smith put it, Ch.3, Of Public Debts, “Were the expense of war to be defrayed always by revenue raised within the year … wars would in general be more speedily concluded, and less wantonly undertaken.”

So far, Republicans have been able to delude voters and perhaps themselves that the budget can be balanced without higher taxes, and by cutting only domestic discretionary programs. When reality finally sets in and they have no choice but to accept that this is impossible, establishment conservatives like Brooks, Feulner and Kristol must decide which is more important to them: opposing all tax increases or preserving the defense budget. We will then find out if they genuinely care about our national security or are what Thomas Paine called summer soldiers and sunshine patriots.