An Austrian Review of Robert Mundell’s “Difficult Trinity”

Robert Mundell, winner of the Economics Nobel in 1999, recently passed away at the age of eighty-eight. As a number of the obituaries have discussed, Mundell is considered the intellectual father of the euro and was associated with the supply-side revolution in economics in the early 1980s. Nevertheless, in this short article I will focus on his earlier, influential deal with financial and trade theory– which won him the reward– and critique it from an Austrian viewpoint. Specifically, I will describe what is implied by Mundell’s “difficult trinity,” and then show why a hard-money Misesian would decline its evident insight.

Mundell’s Difficult Trinity

Although I often take shots at him, Paul Krugman actually had a great explanation in Slate of Mundell’s contributions back in 1999 when he (Mundell) was awarded the Nobel. For our functions, I’m replicating here the appropriate portion of Krugman’s column. The quotation is rather lengthy but it’s great in the beginning setting the historic context and after that discussing (in layman’s terms) what Mundell demonstrated:

Here’s what the world looked like in 1960: Nearly all countries had actually repaired exchange rates with their currencies pegged to the U.S. dollar. International movements of capital were dramatically limited, partly by federal government guidelines, partially by the memory of defaults and expropriations in the ’30s. And a lot of economists … took it for given … that this was the method things would continue to work for the foreseeable future.

However Canada was various. Controlling the motion of capital across that long border with the United States had actually never ever been practical; and U.S. investors felt less nervous about putting their cash in Canada than anywhere else. Provided those uncontrolled movements of capital, Canada could not repair its currency exchange rate without giving up all control over its own monetary policy. Unwilling to end up being a financial ward of the Federal Reserve, from 1949 to 1962 Canada made the nearly special decision to let its currency float versus the U.S. dollar. Nowadays, high capital mobility and a varying currency exchange rate are the norm, but in those days they seemed outrageous– or would have appeared outrageous, if anyone but the Canadians had actually been involved.

Therefore maybe it was the Canadian case that led Mundell to ask, in among his 3 most well-known contributions, how monetary and fiscal policy would operate in an economy in which capital streamed freely in and out in reaction to any difference in between interest rates in your home and abroad. His answer was that it depended on what that nation did with the exchange rate. If the country insisted on keeping the value of its currency in regards to other countries’ cash constant, financial policy would end up being completely impotent. Just by letting the exchange rate float would monetary policy regain its efficiency.

Later Mundell would expand this initial insight by proposing the idea of the “difficult trinity”; free capital movement, a set currency exchange rate, and an efficient monetary policy. The point is that you can’t have it all: A nation must choose two out of 3. It can fix its exchange rate without emasculating its reserve bank, however only by preserving controls on capital circulations (like China today); it can leave capital motion totally free but retain monetary autonomy, however only by letting the currency exchange rate vary (like Britain– or Canada); or it can select to leave capital totally free and stabilize the currency, but just by deserting any capability to change rates of interest to fight inflation or economic downturn (like Argentina today, or for that matter the majority of Europe).

Elaborating on the Impossible Trinity

Although Krugman’s summary was written in plain English– readers who desire a more technical account with citations to the literature should take a look at the Wikipedia entry on the “Mundell-Fleming model“– let me elaborate a bit, to make certain the reader comprehends the dynamics involved.

Picture the United States is initially in equilibrium with Japan, and it takes $1 to buy ¥ 100 in the foreign exchange markets. Now suppose that at current rates, rate of interest, currency exchange rate, etc., American consumers suddenly want to spend $1 billion more on Japanese cars and trucks, and that this is not counterbalanced by any desire from Japanese consumers to import more American-made goods. What occurs? We will evaluate the 3 possibilities from a Mundellian point of view, letting the authorities pin down each of the components in the “impossible trinity” in the particular choices. (Keep in mind that our conversation of the very first alternative will be the longest, while we established the framework, so that our conversations of options 2 and 3 can be quick.)

Mundell Alternative # 1: Select complimentary capital motion and effective/independent financial policy, while giving up a fixed currency exchange rate (i.e., allowing versatile exchange rates).

In this very first scenario– which represents the policy suite adopted by the United States and Japan today, incidentally– the authorities would allow the desired transactions to go through; the US customers would get to purchase their $1 billion in extra vehicles. This increase in the trade deficit would be matched by a corresponding Japanese financial investment of financial capital in the (net) build-up of American possessions.

In concept, the Americans might actually send hundred-dollar expenses across the ocean that the Japanese would then contribute to their safety-deposit boxes; this would show the Japanese increasing their portfolios by $1 billion worth of American-issued financial assets (specifically, currency). However, a more common outcome would be that the American importers would first enter the forex markets with their $1 billion and utilize them to buy Japanese yen. They would then use the yen to purchase the automobiles from the Japanese sellers, who (obviously) usually perform their organization in their own domestic currency. On the other hand, those in the forex market who had sold their yen for dollars would then take the brand-new $1 billion in US money to buy American properties, such as Treasury debt, United States stocks, realty in Miami, etc.

. Now here’s where things get tricky. In this situation, we are supposing that the important things that disturbed the original stability is American automobile purchasers suddenly choosing to import extra lorries from Japan. The only method to make that boost in the trade deficit “balance” is for Japanese financiers to increase their investment in American possessions– which keep in mind, can be financial obligation claims– by an equivalent amount, measured in dollars.

However if we were originally in stability, where Japanese financiers enjoyed with their holdings of American possessions, then to induce them to hold an extra $1 billion worth, the American properties have to become more attractive. Specifically, their anticipated yield needs to increase. In the case of Treasury securities, that indicates the interest rate on United States federal government debt needs to increase, so that the Japanese financier is willing to include more of it to his portfolio than in the past.

Yet hold on. In this Mundell Option # 1, the central bank is still enabled to practice “reliable monetary policy.” Presumably the Federal Reserve doesn’t desire to let US rate of interest increase above its original target level even if American vehicle buyers desire more Japanese vehicles. So if the American and Japanese authorities are going to allow the wanted deals to go through– therefore preserving complimentary capital motion– and the central bank is going to maintain control over its monetary policy decisions, then the Fed will act to fight the upward pressure on rate of interest.

Typically, the Fed will participate in open market operations (which I explain in this chapter), buying properties from the market while developing additional dollars “out of thin air.” By flooding the credit markets with brand-new reserves and by taking Treasury debt onto its own balance sheet, the Fed’s actions will lower US interest rates back to the original target level.

All of the extra money printing will move exchange rates, however. (Remember, in Mundell Option # 1, the aspect of the trinity that couldn’t be kept was a fixed exchange rate.) In order to restore stability, the US dollar will fall versus the yen, so that instead of purchasing the initial hundred, maybe now a dollar just trades for ninety-nine yen. Other things equivalent, as the dollar deteriorates against the yen, it makes Japanese automobiles appear more costly to American importers, and so this movement in exchange rates will stanch the new circulations of automobiles and capital.

Now that we have actually carefully walked through the information of one leg of the “impossible trinity,” we can rapidly cover the other two.

Mundell Option # 2: Pick a fixed exchange rate and effective/independent financial policy, while giving up totally free movement of capital.

This second scenario is rather easy to discuss: when our hypothetical American customers want to import more Japanese cars– or if Japanese financiers want to buy more American assets– the respective authorities simply say no. By strictly restricting global deals to only authorized channels and amounts, the authorities keep a free hand to set whatever targets they want for domestic rates of interest and the foreign exchange rates on their currencies. If their residents grumble that they see a better car deal or bond readily available in a foreign nation, their political officials tell them, “Hard! If you’re so dissatisfied here, move to Somalia.”

Mundell Alternative # 3: Pick totally free capital motion and a fixed exchange rate, while giving up control over financial policy.

In this third and last scenario, we suppose that the American and Japanese authorities wish to enable their citizens to import automobiles and export financial capital nevertheless they ‘d like. However, they do not desire the vagaries of consumer and financier demand to impact the USD-JPY exchange rate, which (we expect) is completely secured at 1:100.

Therefore, when American importers wish to buy more Japanese cars and trucks, therefore putting upward pressure on US rates of interest (to cause Japanese investors to hold the matching additional amount of American properties), the Federal Reserve has to allow it. This holds true even if the Fed’s own views on unemployment and inflation say that a “rate walking” would be bad for the US economy. Certainly, not just would the Fed not take part in looser policy (as in alternative 1), but depending on the specifics it may really need to sell some of its own properties and soak up dollars from the system in order to keep the dollar from falling against the yen. Other things equal, Fed officials may fret that such tightening would slow US financial growth and keep United States joblessness higher than they wanted, however such is the corner into which Robert Mundell has actually painted them.

An Austrian Review of Mundell’s Difficult Trinity

Undoubtedly, my narrative above was somewhat loosey-goosey; perhaps Krugman would have described the cause and effect differently (see for example this Wikipedia entry), and Mundell in his published papers of course defined a formal model with all the i‘s dotted and t‘s crossed. Even so, I’ve provided a fair flavor of what Mundell meant by his declared “difficult trinity” or what is likewise called a “policy trilemma.”

Yet from an Austrian point of view, this obvious tradeoff is spurious, particularly in the long run. Under the classical gold standard (which dominated amongst the innovative nations approximately the eve of the First World War), the getting involved nations delighted in complimentary movement of capital, repaired currency exchange rate, and their central banks were practicing the most “effective” financial policy in battling economic downturns that was offered to them. In this regard the situation is comparable to the alleged tradeoff in between flexibility and security: when citizens give up their liberties so that the authorities can (supposedly) protect them, they end up exposed to more danger.

I describe the operation of the classical gold standard in great detail in this chapter. For our functions here, I will highlight 2 bottom lines:

First, under the classical gold requirement, each sovereign country specified its own currency in regards to a specific weight of gold. This implied a fixed currency exchange rate between these sovereign currencies. For example, in the year 1913, the British federal government stood ready to redeem its currency at the rate of ₤ 4.25 per ounce of gold, while the US government would redeem its currency at the rate of (around) $20.67 per ounce of gold. These particular policies indicated– using easy arithmetic– that the currency exchange rate in between the currencies was fixed at about $4.86 per British pound.

Yet this currency exchange rate between the dollar and the pound wasn’t “fixed” by browbeating, in the sense of actual rate controls; there was still a free enterprise in forex. What happened in practice was that if the real market exchange rate of dollars for pounds deviated too far from the anchor point of $4.86, it would end up being profitable for currency speculators to ship gold from one country to the other in a series of trades that would push the marketplace currency exchange rate back towards the “repaired” anchor point. (See my chapter for more details on how this worked.)

The benefit of a repaired exchange rate is that it permitted individuals to make financial strategies involving foreign commerce far more confidently, since they wouldn’t need to fret about movements in each currency. Imagine the problem of being an American business owner if each of the fifty states issued its own fiat currency that “drifted” versus all the others.

The second indicate highlight is that yes, Mundell is right that under the classical gold standard, the central bank had to subordinate its other policy goals to maintaining adequate gold reserves. If changes in consumer and investor mindsets put downward pressure on a nation’s currency, this would cause gold outflows. If the reserve bank were to preserve the fixed redemption rate of its own currency in gold, it would need to reverse this outflow of gold, and so the reserve bank would have no option however to tighten its financial policy, by slowing the creation of new currency (and even soaking up a few of the exceptional stock), and/or permitting domestic interest rates to increase.

Yet if the Austrian theory of the business cycle (discussed here) is correct, then letting markets– rather than reserve banks– determine rate of interest is exactly the method to prevent the boom-bust cycle that so pesters market economies. To put it simply, what Robert Mundell or Paul Krugman refer to as “independent” or “efficient” monetary policy needs to in fact be equated as “the tool with which central banks sustain an unsustainable boom that leads undoubtedly to a crash.”

Now it’s true that even under the classical gold requirement, the marketplace economies suffered from regular panics and depressions. But even here– if Mises is right in his medical diagnosis— the problem is that even the business banks have too much “discretion” over interest rates, stemmed from their ability to create and damage cash (broadly defined). So to be clear, I am not in this essay declaring that the classical gold standard by itself prevented recessions. Rather, I am stating that connecting the central bank’s hands– in a way that a Mundellian might refer to as “forfeiting efficient financial policy”– is an essential (but insufficient) condition to remove the boom-bust cycle.


Fans of the Austrian school would take advantage of learning more about the Mundell-Fleming model, at least intuitive descriptions. I understand that I personally comprehended more about international trade and capital circulations after working for Arthur Laffer, who himself published in this structure. To be clear, the canonical Austrian treatments (such as in Mises and Rothbard) of these subjects are correct, but there are subtleties that Person Action and Man, Economy, and State do not cover.

Nevertheless, what a lot of economists conclude from Mundell’s theoretical analysis is however incorrect. To wit, we don’t do any favors for economic growth or the labor market by offering central bankers a “freedom” to create money and set rates of interest however they please. Later in his career, when he became connected with the supply-side revolution, Mundell himself might have embraced the virtues of difficult money and shunned macro “fine-tuning,” but his insights still pale in comparison to those of Ludwig von Mises.

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