A somewhat critical reader pointed out recently that my commentaries as of late have concentrated heavily on the foreign policy debate currently taking place in the Republican Party; in which once settled terms like “isolationist” are now called into question; the neoconservatives’ long dominant influence on the party becomes more clear and troubling; and a critical eye is cast on the formerly solid GOP consensus promoting muscular foreign interventionism—now that the Bush Doctrine has become Obama’s too.

I told this reader that the argument over the GOP’s foreign policy consensus is the most important debate taking place in America today. My reader disagreed, saying that, no, the battle over the national debt and whether to raise the debt ceiling was the most important debate.

“Yes, exactly” I replied. He seemed confused. He’s not alone.

Every politician now says we need to significantly reduce our national debt. The Democrats’ eternal answer is to cut virtually nothing and to increase revenue by raising taxes. The only thing this would do—and all it has ever done—is give Washington, DC the ability to spend more money. This is the reason we have such massive debt in the first place.

Our only hope for reducing the national debt currently lies with the Republican Party, but only a very small handful of Republicans are serious about reducing it. The current hoopla over whether or not to raise the debt ceiling is primarily a debate over simply capping spending, not cutting it. Rep. Paul’s Ryan’s controversial entitlement reform plan is primarily aimed at saving Medicare, not reducing spending. When the Republican-controlled House was given the chance to actually fight for spending cuts in April, it settled on $38 billion in “cuts” to proposed future spending—and even this bit of useless politicking was later reduced to a measly $352 million. Remember, our national debt stands at well over $14 trillion. Clearly the Republican Party of John Boehner is not serious about sizable spending cuts.

So who is? The most significant Republican proposal to actually reduce spending to a degree in tune with the severity of our problem was put forth by Sen. Rand Paul. Paul introduced a plan in March that would balance the budget in five years and reduce the debt by $4 trillion. Paul’s plan sought not simply to stop or reform spending—but to cut it—the very thing virtually every Republican claims to support and agrees must happen.

Paul’s proposal failed in the Senate 7-90. All seven “yea” votes were Republican.

Sen. Jim DeMint of South Carolina was one of those Republicans. During an interview on WTMA talk radio in Charleston, South Carolina last week, talk host Richard Todd asked Sen. Lindsey Graham about his South Carolina colleague’s “yea” vote: “I wanted to ask you Sen. Graham because I know you want to try to get us out of debt. Sen. Rand Paul proposed a budget… that got seven votes… one of them was Jim DeMint… one of them was not yours… so we want to know why you would not have supported a budget that would have balanced the budget in five years, getting serious about it?”

Replied Graham: “I’m not going to vote for any budget that reduces defense spending by over 40%. And I’m not going to vote for any budget that reduces our defense capabilities at a time we’re under threat.”

It was reported last month that the total cost of our Middle East wars post-9/11 stands at $3.7 trillion. This is just the official number—which should be taken about as seriously as Obama’s official cost of national healthcare. $3.7 trillion is also roughly four times the cost of Obamacare—which virtually every Republican agrees America cannot afford.

The largest expense in our annual budget is entitlements. The second largest is defense spending. Republicans like Graham often go to great lengths to point out that defense doesn’t really cost that much. Yet when these same Republicans are asked why the size of government and debt doubled under President Bush, what’s their typical answer? We were fighting two wars.

They can’t have it both ways.

Yet to date, Republicans have. In supporting the U.S. intervention in Libya, encouraging one in Syria, and advocating a permanent American presence in Afghanistan, Graham is certainly one of the more hawkish Republicans. But the extent to which his party agrees with him on foreign policy is a primary source of our debt problem, and if you asked each Republican who opposed the Paul budget their reason for doing so, chances are you would get an answer similar to Graham’s.

Few Republicans have offered any alternative budgets to Paul’s that feature actual cuts (the most notable would be Sen. Pat Toomey’s, which also recognized the necessity of defense cuts), precisely because achieving such a feat must include a reduction in Pentagon spending. Only six of Paul’s GOP colleagues appeared to understand this mathematical truism last March.

We spend more on defense now than at any time in our history since World War II and 72% of Americans now say the U.S. does too much around the world. The current debate in the GOP presidential primaries is whether the party will remain that of Bush—one that continues to police the world through countless open-ended commitments for questionable reasons at an exorbitant cost—or become a Republican Party that believes there are practical and fiscal limits to what our military can achieve around the globe.

America’s ability to finally reduce its national debt hinges upon the outcome of this debate.