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Photographer: Kostas Tsironis/Bloomberg

Like Greece, the United States shoulders a worrisome government debt that's growing larger each day. It can therefore only be a matter of time before the fiscal meltdown gripping Athens reaches American shores, right?

That's a popular argument, but it's nuttier than fresh karydopita.

True enough, both countries owe plenty relative to the size of their economies. By the end of this year, Greek debt will total about 150% of its gross domestic product. U.S. debt will be close to 100% of GDP under a broad measure that includes sums the government owes itself (like Treasury bonds held by the Social Security Trust Fund). Both countries are quickly digging deeper holes at the moment, with deficits expected to total around 10% of GDP this year.

That's where the similarities end, however. The most remarkable attribute of America's fiscal challenges is just how fixable they are. Uncle Sam is three manageable steps away from erasing its budget deficit and then some.

America's 10% deficit comes from collecting 15% of GDP in federal taxes--the lowest level of taxation in 60 years--while spending 25%. Both figures have been knocked out of whack by temporary events, chiefly: massive war costs, aggressive stimulus spending and tax cuts that are more accurately described as loans because they were never paid for. The wars are winding down, taxpayers show little tolerance for more stimulus and the "tax cuts" expire next year. Step one, then, is simply letting things revert to normal. What will that look like? Between 1971 and 2010 federal taxes averaged 18% of GDP and spending averaged 21%. Normal is a 3% deficit.

Changes No. 2 and No. 3 would close that gap and then some.

Start with health care. The U.S. spends more than any country in the world by a shocking margin, and achieves health outcomes that are no better than those in other rich countries. It spends 16% of GDP, including government payments, health plan premiums and out-of-pocket costs. The second-biggest spender, France, pays 11% of GDP. That means that if the U.S. were to overhaul its health system by adopting a plan from either the political left (Medicare for everyone) or right (vouchers), it could save 4% of GDP and still be the biggest spender in the world. Since current spending is half public and half private, half of the savings would go to reduce the deficit to 1% of GDP. The other half--about $2,600 per household, per year--would go into American pockets.

Now look at defense. The U.S. is alone among peers today in spending nearly as much today as it did during the Cold War. Last year it spent an unparalleled 5.4% of GDP. Britain, the closest comparable nation, spent 2.7%. Worse, relative to peers, the U.S. under-spends on soldiers and overspends on equipment. There's plenty of spending to be cut before capability is compromised. Big spenders are supposed to achieve something called economies of scale, meaning that the U.S. should be able to spend well less than Britain's 2.7% of GDP for a military much larger and better-equipped than that of Britain. But let's say it reduces spending only to 3.4% of GDP. It would still outspend every nation on Earth by a vast margin, and the 2% of GDP saved would turn that aforementioned 1% deficit into a 1% surplus.

Those are just three changes, keep in mind, and only two involve doing something, and that something is to go from being No. 1 in spending to still being No. 1, but by a smaller margin. Those aren't the sort of austerity measures that lead to rioting in the streets. I haven't addressed state and local spending, but suffice it to say that if America fixes health care at the federal level, the states will be awash in spare cash, too.

Greece can't make any of these easy cuts, in part because it already collects a staggering 39% of GDP in taxes--and somehow manages to spend 49%. Its spending isn't the result of a temporary surge, but rather, of deep structural flaws. Its healthcare system and military don't lend themselves to easy cuts because their costs are already in line with those of peer nations. GDP per head in Greece is less than two-thirds what it is in the U.S., which limits flexibility.

Perhaps this is why, for all the talk about similarities between Greece and the U.S., short-term Greek bonds recently yielded 30%, a sign that investors only half-expect to be paid, while short-term U.S. bonds yield less than 0.5%, suggesting they're one of the world's safest investments.

Bottom line: The changes needed in Greece are going to be painful for ordinary Greek families, which is why so many there are understandably outraged. The changes needed in America will reduce the profits of health insurers, defense contractors and perhaps their lobbyists, but leave most Americans unscathed. That's not austerity. It's better use of abundance.