Editor’s Note: The author is a lawyer at a Chicago law firm.

The “Panama Papers” obtained by journalists from hackers who hacked into the Panama law firm Mossack Fonseca’s computers made a resounding impact in a very short time. The Prime Minister of Iceland, David Gunnlaugsson, whose papers showed he owned offshore shell companies, resigned when this came to light. Vladmir Putin rejected the papers — some of which showed his associates doing the same — as a U.S. plot to discredit Russia. For U.S. lawyers and their clients, the Panama Papers raise questions not only about cybersecurity — an issue already firmly on their radar — but also on clients based outside of the U.S. or transacting business outside of the U.S. and non-U.S. co-counsel working with them.

How U.S. lawyers assist non-U.S. clients and non-U.S. activities was an issue that made a splash earlier this year when Global Witness secretly recorded U.S. lawyers meeting with a supposed representative of a minister of mining in a West African country who wanted to park his wealth in ostentatious assets in the U.S. Some of those video vignettes landed on 60 Minutes.

As President Obama noted when the Panama Papers story broke, “There is no doubt that the problem of global tax avoidance generally is a huge problem. The problem is that a lot of this stuff is legal, not illegal.” Beyond tax avoidance, impenetrable shell companies in remote jurisdictions also raise concerns about money laundering and financing of terrorism.

For U.S. lawyers, the reason why “a lot of this stuff is legal” is rooted in respect for the attorney-client privilege, and the Model Rules of Professional Conduct, enacted to some degree in 49 states. In the U.S., “a lawyer shall not counsel a client to engage, or assist a client, in conduct that the lawyer knows is criminal or fraudulent.” Thus, a lawyer here can turn a blind eye, as long as he doesn’t know that the client is engaging in a crime or fraud. To be fair, the American Bar Association has recommended that lawyers not turn a blind eye and do “client due diligence.”

Under confidentiality rules, U.S. lawyers are bound to protect client confidences. We are obligated to report our clients to authorities rarely — then only in some states (such as Illinois) and only when the client is likely to cause death or serious bodily harm. U.S. lawyers are given slightly broader latitude about things we may choose to report, such as reporting to prevent a client from committing other crimes, or serious frauds that will harm others. These same confidentiality restrictions apply even to prospective clients who consult with lawyers but do not become clients.

However, we need only look to Europe and particular the U.K. to see a wholly different regulatory regime covering what lawyers must report to authorities about clients and prospective clients. The European Parliament’s “third directive” on money laundering and terrorist financing mandates customer due diligence and reporting of suspicious activities to authorities, without notice to the customer, for a range of institutions that includes lawyers and law firms. These are similar to “know your customer” requirements imposed upon U.S. banks, but not upon lawyers. In the U.K., the Solicitors Regulation Authority requires British solicitors to do likewise. The Law Society of England and Wales has extensive rules on customer due diligence. Politicians as clients, so-called “politically exposed persons,” such as the Prime Minister of Iceland or associates of Mr. Putin, are met with extra scrutiny. British solicitors are also required to make suspicious activity reports (SARs) concerning suspected money laundering to law enforcement authorities.

The European and U.K. regulatory regimes also call into issue a lawyer’s reliance on persons in other countries, such as Mossack Fonseca in Panama. A British lawyer can rely on a foreign lawyer’s customer due diligence only if that lawyer is subject to requirements equivalent to the European Parliament’s third directive. Needless to say, the rules governing U.S. lawyers are not the equivalent of the EU’s regulatory regime.

The European and British regulatory regimes are sharply at odds with the Rules of Professional Conduct governing U.S. lawyers. Reporting requirements conflict with our notion that protecting the attorney-client privilege and safeguarding our clients’ confidential information is a fundamental charge given to our profession. Change will not be driven by American courts and bar associations any time soon.

If lawyers are going to be enlisted to help stop tax avoidance and money laundering, it is Congress who will have to act. Despite Congress’ fondness for anti-terrorist legislation, it is deeply uncertain at best that a Republican-controlled Congress devoted to cutting taxes for the wealthiest people and reducing the IRS’ budget will take steps to make sure that their constituents, and they themselves, cannot establish shell companies in Panama or other offshore havens — or, for that matter, in Delaware, Nevada or other states.

If the Panama Papers provoke a debate, both sides will have powerful arguments. The attorney client privilege is designed to encourage people to get legal advice and comply with the law. Know-your-customer and reporting requirements encourage the payment of badly needed tax revenues and help prevent criminal activity. One middle ground short of requiring suspicious activity reports could lie in requiring U.S. lawyers to perform customer due diligence, rather than just recommending it. In effect, lawyers could be required to a degree to educate themselves about prospective clients and their activities rather than turning a blind eye. If that due diligence raises concerns about criminal or fraudulent activity, attorneys would then be required to turn the work away. Whether U.S. bar associations, courts that have the power to supervise lawyers, and Congress can agree on such a step remains to be seen.