Treasury’s War is an unusual book. Given the way it reads, its subtitle might well have been “A Bureaucratic Adventure Story.”

Don’t roll your eyes—the genre really does exist. Government whistleblowers often put into books the story of what they did to foil policymakers (most always unsuccessfully). Most of these bureaucratic romances are about bad policies and the failure to avoid them despite the author’s sage advice. Treasury’s War is very different. Juan C. Zarate describes a bureaucratic success. That is to say, his is a tale of how bureaucrats did something new and useful by defeating the usual inertia and the even more usual meddling of policymakers. Temporary? Yes. But instructive.

Zarate tells the story of how, in the wake of the attacks of September 11, 2001, a small group of Treasury Department bureaucrats took advantage of Section 311 of the Patriot Act—which allows the department to designate any bank in the world as a “primary money-laundering concern” and prevent it from doing business with any American bank—and actually made it useful in combating terrorist groups and rogue states. In effect, it’s a story of sanctions that worked thanks to will, ingenuity, and prudence.

To the layperson, it will seem that Treasury’s sanctioning of banks that facilitate illicit transfers and money laundering must have been common sense. Of course we shouldn’t let banks that do business with our enemies do business with us. A further obvious thought would be something like, “Ah, yes! The world financial system depends on America, the dollar is the reserve currency, and then there are the New York banks. If a foreign bank is kept from doing business with us, it’s in trouble.” Still further along the line of reasonable assumptions: “This is war by other means, war by shaming. The Treasury Department pins a bad reputation on this or that bank, and depositors—the dubious and the honest alike—go elsewhere.”

The idea may be graspable, but putting it into effect is a very different matter. The world financial system is enormously complex and delicate. In order for it to function, there needs to be a kind of integrity that keeps it away from international politics. Any state’s dealing with it in any new way is fraught with danger. The chief risk is of being shut out of parts of the world financial system. The other big risk is turning the system into a political battleground.

Much of Zarate’s story has to do with negotiation. In order to know whom to sanction, Treasury needed information from the financial industry itself. It may come as a surprise that our intelligence community has traditionally provided relatively little in that regard. Perhaps not as surprising is that financial institutions are less than eager to disclose with whom they’re dealing. The real story of Treasury’s success is not so much effectively implementing a new form of sanction, but getting the information to do so.

The key to Treasury’s success was its negotiation with the Society for Worldwide Interbank Financial Telecommunication (SWIFT), the European-based transactions clearinghouse. SWIFT is crucial to following foreign money, but in order to do its job, secrecy is of the utmost importance, lest banks cease reporting their transactions. Its files are only open to law enforcement when indictments are made. Even then, there is great reluctance at SWIFT to cooperate.

When SWIFT learned that Treasury was interested in tracking, not just where certain well-identified terrorists and bad state actors were moving money, but banks’ confidential activities, its resistance was considerable. Nonetheless, Treasury bureaucrats managed to win SWIFT’s cooperation and created the Terrorist Finance Tracking Program. Managing that program required continuous negotiation with SWIFT and an evolving self-regulation scheme.

Perhaps the best and most illustrative story of a “311” bank sanction by Treasury regards North Korea. In 2005, in response to that country’s involvement in counterfeiting and drug-trafficking, the United States hit Banco Delta Asia in Macau with a “311” for doing business with North Korea. Very quickly, banks throughout Asia, and even in China, began turning away North Korean government business. The Banco Delta Asia sanction temporarily isolated Pyongyang from the international financial system.

As Zarate tells the story, North Korea shot a missile into the Pacific as a response and the State Department was upset with Treasury. North Korea appealed the “311” with State and the latter began negotiations in Beijing. These ended when a Chinese bank volunteered to handle some of the money that the authorities in Macau had frozen. But, surprise!, the Chinese central bank refused to permit this. It wanted nothing to do with Banco Delta Asia.

This story doesn’t have a happy ending, unfortunately. The State Department insisted on easing Treasury’s pressure on North Korea. By dint of their “missile rattling,” Zarate says, “the North Koreans had expertly turned the tables” on the United States. “We were outmaneuvered at the height of international pressure and gave up our leverage.”

Treasury’s initial impressive effect of sanctioning the Macao bank illustrates how well the Section 311 action worked and can still work. But the story’s ending tells the all-too-familiar tale of how politics and foreign policy limit good laws and effective action by government agencies.

These days, it behooves us all to learn more about how the international financial system works and, especially, about how the system’s eternal tension between integrity (which no financial system can do without) and the profit motive (which no one can resist) manifests itself now. A prominent recent case is the U.S. sanctions taken against the biggest French bank, BNP Paribas, for doing an enormous business with Iran, Sudan, and Cuba, all of which are and have been under U.S. and other sanctions. BNP agreed to pay a fine of $8.97 billion in order to be spared from severe criminal indictments and to maintain its U.S. operations. The only other Treasury action taken against BNP was a temporary suspension of interbank and oil and gas dollar-clearing facilities.

The nearly $9 billion fine was a record, the previous one being a mere $1.7 billion paid by HSBC in 2012. It turned out that BNP Paribas had willfully dealt with sanctioned entities, had anticipated Treasury’s actions, and possessed the reserves to cover the fine. The scale of BNP’s depredations caused numerous commentators to resurrect the line from the financial crisis of 2007 and 2008, “Too big to jail.” The sort of thing that Zarate and his Treasury colleagues sought to block with fines and curtailed business privileges now must seem to them, given the BNP case, far more difficult to deal with. It shows that if the bank is big enough and well prepared, it can treat such an enormous fine as “just another cost of doing business.”

International money laundering is an ever-moving target. We may see even bigger settlements and, for the first time, substantial criminal indictments. As the BNP case suggests, however, the depredations that bring a real punishment may never be big enough. Also, at some point given the size of fines, it’s likely that international politics will come into the matter and put the United States at serious odds with other states. And international information sharing will end.

Treasury’s War, by showing what ultimately happened in the Banco Delta Asia “311,”unfortunately returns us to where things have always stood with trade and economic sanctions. Even the best-laid plans of those who implement them have eventually been, as a wise friend says in a soon-to-be-published study,

undermined by opposition and evasion on the part of elements of the sanctioning government itself, by allied and other countries which wish to continue to do business with the sanctioned country, and by domestic industrial, commercial and financial interests.

He goes on to say:

Economic sanctions will continue to proliferate since they permit the sanctioning government to say it is doing something more than rhetorical to mollify domestic and international pressure groups demanding action. In the rare cases where there is no failure of will or perseverance, they can, indeed, be very powerful.

One only need to look at the fate of U.S. sanctions against Iran—perhaps the most elaborate ever to occur outside the context of war—to see where we are now. Even partial breaks in disciplined enforcement invariably lead to erosion of entire sanctions regimes. In the case of Iran, their partial removal to facilitate negotiations on Iran’s nuclear program has led to the end of Iran sanctions, for all intents and purposes. Under current political conditions, the United States may still try to enforce the sanctions still in place, but the world is ignoring us—as well it might, now that we’ve let on that the nuclear talks are more important to us than maintaining sanctions.

Although it’s a story for another occasion, it is apt to mention here that there was a time when U.S. economic sanctions were significantly effective: during the Reagan administration’s strategic exercise to win the Cold War. The economic measures included limiting the Soviet Union’s foreign exchange earnings by cutting off funding for the second Yamal gas pipeline to Western Europe, and ending the highly favorable financial terms attached to loans to Moscow and its satellites. The Reagan administration also curbed Soviet theft of technology by a program of deception that gave Moscow’s spies altered plans and blueprints to make sure that devices constructed according to them would not work.

The Reagan approach to economic warfare was, in contrast to sanctions since, well supported by diplomacy, propaganda, subversion, and the demonstration of U.S. military capabilities. Reagan’s successes and Treasury’s War both show clearly the role of will and well-thought-out policy in waging war by economic means. These qualities were present immediately after the September 11 attacks. What are the odds that we will we see them again?

Treasury’s War, although a very thick book, has necessarily left out a number of related—and important—topics. Even in a realm like finance, where confidentiality is in everyone’s interest, the gathering of information on a large scale (which the relationship between Treasury and SWIFT makes possible) has to be a concern. SWIFT is quite right to be nervous about the circulation of data. The fear is, rightly, that information not tightly held and put to one purpose and one purpose only, invites evasion and politicization.

Given the U.S. government’s lack of cyber security and the propensity of those within it to leak for political advantage, one might well ask what brakes there are to prevent political abuse of financial information. Furthermore, could irresponsible handling of the information at Treasury—or its use to unenvisioned ends by other government agencies working at cross-purposes with one another—lead to financial disruptions detrimental to the U.S. economy? Inasmuch as the federal government takes no real responsibility for protecting the commercial sector, one would do well to ask what assurances there are that the sanctioning of foreign banks does not hurt Americans in the private sector.

Even when sanctions regimes are properly created and administered, they are notorious for causing the sanctioning country as much trouble as the one being sanctioned. The law of unintended consequences comes into play. In the current global economy, the U.S. private sector is more vulnerable than ever to what might be called “sanctions rebound”—the collateral damage to one’s own economy caused by damaging another.  Accordingly, Washington might think twice regarding whether it is prudent to place sanctions on the scale applied to Iran the next time it wishes to substitute them for armed conflict.

“Economic warfare,” a concept developed by the British before World War I in order to strangle the German economy, has become fashionable these days because of state-sponsored terrorism, cyber espionage, and the theft of commercial secrets. It is looked upon as an increasingly important arrow in the quivers of our adversaries. Indeed, it shows up in Chinese strategic doctrine and is suggested by Iran’s destruction , in 2012, of 30,000 Aramco computers in Saudi Arabia. The temptation to use it ourselves, as we take up the challenge of cyber security, is strong.  As the British learned before the Great War, committing economic warfare on an effective scale risked shutting down the international financial system. Because of that, Britain chose to limit its economic warfare to a naval blockade cutting off German supply lines.

Today, in a more globalized economy, the collateral damage of the greater use of economic warfare—even to cut off terrorist funding—is far more difficult to measure.  While terrorism seems to have become more local and regional since the heyday of al Qaeda, the role of state sponsors like Iran, Qatar, and Turkey remains central and crucial.  Committing aggressive economic warfare against them raises the specter of considerable negative results for us.

Not to slight Treasury’s War as a book, one must say that it is not for everyone. Stylistically, it veers between being a novel and a Congressional Research Service report. The details of what happened are vital to it, but such details will leave most readers’ heads spinning. That said, there is much of interest in Juan Zarate’s account, and it can be “read around in” with profit according to one’s interests and knowledge of events in the time period it addresses.