Few American laws have been as controversial as FATCA. FATCA stands for Foreign Account Tax Compliance Act, a law passed in 2010 to clamp down on the use of foreign bank accounts by U.S. taxpayers to hide money that is otherwise subject to taxation in the United States. FATCA is the U.S. government’s newest enforcement tool in the fight against international tax evasion.

Those that denounce the law criticize its complexity, its expansive reach, and the high cost of compliance. Those that like it (and there are some) argue that it will blow the lid off of “the old way of exchanging tax information between countries on request,” which they view as too lenient on tax cheats. FATCA, they predict, will revolutionize the exchange of information, by making it “automatic,” thereby removing any safe harbors for those who have, shall we say, less-than-pure motives.

What is it about this pestilent law that engenders such strong emotions? Very simply, it turns foreign banks and financial institutions into enforcement arms of the Internal Revenue Service (IRS). Foreign financial institutions are put in the untenable position of having to choose between disclosing account information on clients who are “U.S. persons,” on the one hand or paying a whopping 30% of all payments they receive from America to the IRS, on the other. Although they seemingly have two “options,” most foreign financial institutions would argue that they have only one real option if they want to be around long enough to report next year’s quarterly earnings, and that is to succumb to Uncle Sam’s heavy-handed demands and turn over U.S. accountholder information.

Regardless of what side of the fence you are on, recent statistics support the notion that the threat is having the effect that it was intended to have. More than 77,000 financial institutions have signed up. And approximately 80 countries have entered into agreements with the U.S. to permit their banks to surrender information to the IRS.

Against this backdrop, there is an enormous amount of confusion (not to mention little guidance) when it comes to interpreting key aspects of FATCA. For example, determining which funds, trusts and other non-bank entities should be classified as “financial institutions” under the law is as much a mystery as trying to find where the body of former teamster boss, Jimmy Hoffa, is buried. And it doesn’t end there.

There is also confusion over a provision that is as fundamental to FATCA as the right to due process is to U.S. citizens under the U.S. Constitution: who is a “U.S. person.” Incredibly, financial institutions have had to guess whether certain accountholders satisfy the definition of U.S. person. In other words, are they the type of persons intended by FATCA for information exchange?

The definition is expansive and includes not only citizens but current and former green-card holders and non-Americans with personal and economic ties to the United States. Some Canadian snowbirds who prefer to trade the cold and desolate tundras for the sundrenched beaches in Miami could be caught in the net, says Allison Christians, a tax professor at McGill University.

As these complexities have surfaced, the U.S. government has had to extend several deadlines. For example, there is a two-year moratorium on enforcement for banks so long as they have made efforts to comply.

FATCA has sent shockwaves through the U.S. expat community, a sizeable population estimated to be a whopping seven million! Thousands are being treated like “second-class citizens” by their once friendly foreign banks. Indeed, many such banks have drawn a line in the sand, saying that they no longer want their business because it is too much hassle. Many others have been forced to spend a good chunk of change trying to straighten out their paperwork with the IRS, even when they owe no tax. In fact, few if any even owe tax thanks in part to the foreign tax credit.

This frustration has caused some expats to take inspiration from the famous line in “Network”: “I’m mad as hell and I’m not going to take this anymore!” Almost 3,000 expats renounced their citizenship or green cards in 2013, not an insubstantial amount in light of how overwhelmingly burdensome the process actually is. Indeed, it makes renewing a license at the Division of Motor Vehicles a “walk in the park.” More than 1,000 did so in the first quarter of 2014 alone. Prior to FATCA, that number paled in comparison: it was just a few hundred a year.

Others have remained citizens but are rising up and fighting back, mounting a powerful uprising that is gaining momentum every day. For example, a Dutch-American citizen sued a Dutch lender that, pre-emptively, closed his account and 149 others. He won the case.

While no two groups have had the wrath of FATCA rain down on them with more fury than foreign financial institutions and U.S. expats, the fact remains that they are not the only two groups to be effected by it. Believe it or not, FATCA even places a burden on the IRS. How so? By creating more work for an agency that is already understaffed. Very simply, the agency is being given more to do with fewer people to do it, leaving it “on the verge of collapse,” according to a former senior official.

The biggest travesty is that for as much pain as FATCA is causing, experts predict that the likelihood of success is slim to remote. These grim predictions suggest that FATCA will fall short of accomplishing its goal. Why you ask? It doesn’t take a rocket scientist to realize that those tax dodgers who are hell bent on using offshore accounts to hide their assets from Uncle Sam are the least likely to open foreign bank accounts in their own names. While FATCA may pierce some of the shell companies they hide behind, Senate investigators and other experts admit that loopholes remain.

Part and parcel of that is the question of whether FATCA is self-sustaining economically. In other words, will it pay for itself? Unfortunately, this question is not susceptible to a “yes” or “no” answer. Instead, the answer is “maybe.” According to Congress, FATCA must net at least $ 800 million a year in order to pay for itself. Ironically, the law was passed without any formal cost-benefit analysis. Notwithstanding, experts believe that the overall costs of complying – a burden carried by non-American banks – will far exceed the additional tax that the IRS would ever collect.

Mark Matthews, a former deputy commissioner of the IRS who is now with Caplin & Drysdale, argues that the effort that has gone into rooting out offshore tax evaders is disproportionate to domestic tax evasion, in the sense that the amount of taxes evaded by the latter far exceeds the former: the sums they (offshore tax evaders) rob from the domestic coffer “look[s] like a pinprick” compared with other types of tax dodging, such as the underreporting of income by small U.S. businesses.

As more countries are pushed to the brink to share tax information, the focus will shift to America’s willingness (or unwillingness) to reciprocate. Who can forget the expression made famous by a dull nursery rhyme: “What’s good for the goose is good for the gander!” For example, consider Latin Americans. Although this group is a large user of banks in Florida, the U.S. has not gone out of its way to share data with Latin American countries.

And when it does, the type of information that it makes available for exchange pales in comparison to the type of information that it demands from foreign banks in exchange. For example, the U.S. only has limited information to exchange on the owners of shell companies. And while it might have a valid excuse – i.e., it does not collect their names itself – it nonetheless makes the U.S. out to be a hypocrite.

Some FATCA partner countries have been even more scathing in their criticism of the U.S., stating that the U.S. is worse than the tax havens it deplores. Do you agree or disagree?