Every time Greece is in the news, I hear mutters about how Americans need to look hard at what happens, because if we don't get our act together, we're headed for the same fate. And every single time, I think "No, that's really not quite right." I could dismiss the muttering, but this time it's louder, including from Republican presidential candidate Bobby Jindal: "Greece will happen here if we do not change course. Anyone who disagrees with this is a 'math denier.' "

So this is where I tell you why it's really not quite right, why the parallels you see are not the only important ones, or even the most important ones.

Everyone who's thinking about policy thinks in metaphors. You have to; situations are novel, and analysis will take you only so far. Eventually you have to fall back on past events to give you a framework for what will happen in the future. The danger, of course, is that you'll grab the wrong metaphor. Saddam Hussein in 2002: Was he Hitler in the Sudetenland or Ho Chi Minh in the Gulf of Tonkin? Was Obama really the second coming of FDR? If you squint, you can always find reasons to choose the metaphor you want — but you will always have to overlook some important differences.

The first thing to note about Greece is that it has a lot of problems, many of which America simply doesn't, and won't for the foreseeable future. Let's list them in order to get a sense of what I am talking about:

1) Small, underdeveloped economy.

2) Long history of default and financial mismanagement that, among other things, made lenders charge them high interest rates to borrow.

3) Broad corruption.

4) Inability to collect the taxes that are levied, both because of the aforementioned corruption, and because Greece does not have a strong civic tradition of tax compliance.

5) Attempting to fix 1 and 2 by adopting an outside currency that hurt exports and left the nation with a monetary policy inappropriate to its business cycle, unable to continue its long tradition of inflating its way out of fiscal and economic problems, and vulnerable to massive capital flight if things fell apart.

6) An unsustainable pension system.

7) Massively unsustainable borrowing to deal with 1, 2, 3, 4, 5 and 6.

8) The worst financial crisis in living memory hitting just as 1, 2, 3, 4, 5, 6 and 7 came to a head.

Now, which of these problems does the United States have? Arguably both 6 and 7, though Greece had the extra-strength, prescription-only, highly addictive kind of pensions and borrowing, and the U.S. is just on baby aspirin.

American policy creates a number of very worrying structural problems that need to be fixed now with some moderate pain, instead of fixed later with quite a bit of agony. This is not the same thing as believing that America is substantially like Greece. Call me back when the retirement age is reduced to 55 and our economy is reduced to tourism and olive trees.

You will notice what I have not said: "America is not Greece because we borrow in our own currency." That's because this is a silly thing to say. "America borrows in its own currency" is not some sort of natural law that follows from our proud frontier spirit and the shapely unfurling of our coastlines; it's something we earn by being responsible stewards of our currency. If we decided to start inflating the heck out of the dollar, then creditors could force us to borrow in some other currency, or demand unacceptably high interest rates in exchange for letting us repay them in American money, rather than changing the stuff into singles and using it to economize on Kleenex.

Moreover, borrowing in your own currency prevents one particular sort of financial crisis, but it does not mean that you are immune from equally gnarly forms of currency crises, banking panics and similar financial dramas. We certainly have the capacity to create within our polity many of the structural problems that have left Greece in such a poor condition; the details might be different, but the effects would be so similar as to require a magnifying glass to explain the distinction to the average citizen.

So while we will never exactly replicate what has happened to Greece, we could certainly end up in a place that was very like Greece; Grecian, if you will. So people who grimly prophesy that a Grecian-style crisis might be somewhere in our future, they aren't demonstrably wrong; they just haven't been right yet.

However, there are two footnotes to this concession. The first is that if such a thing is in our future, it's rather far in our future; we need to tick off a fair number of boxes on that list above before we approach anything comparable. And the second is that while a Grecian future is one possibility for the U.S., it is far from the only one, and it is not even the most likely one. Why would Greece necessarily be the right metaphor? Why not the Roman Empire, or Tsarist Russia, or any number of other countries that came to bad ends? As Adam Smith once noted, "there is a lot of ruin in a nation," and to this we might add the Karenina Corollary: "Happy nations are all alike, but unhappy ones each go to ruin in their own special way." Someday, like all great nations, America will fall, whether it be next year or a millennium hence. Whatever happens, we will have our own crisis, not Greece's.