Gregory Shaffer

Gregory Shaffer is Scott K. Ginsburg Professor at Georgetown University, immediate past president of the American Society of International Law, and has a new book, The Rule of Law under Pressure: A Transnational Challenge.

On Friday, the Supreme Court ruled against the Trump administration’s “Liberation Day” tariff scheme.

Why the Supreme Court’s Tariff Decision May Be Short-Lived Why the Supreme Court’s Tariff Decision May Be Short-Lived

Within hours of losing the case, President Trump declared a new global tariff under a different statute.

Feb 24, 2026 / Michele Goodwin and Gregory Shaffer

President Donald Trump during an executive order signing ceremony in the Oval Office of the White House in Washington, DC, on February 4, 2025.

Trump Doesn’t Have the Authority. What Happens When He Does It Anyway? Trump Doesn’t Have the Authority. What Happens When He Does It Anyway?

The American experiment depends on institutional checks on power’s exercise. If there are no checks, then these indeed will be devastating times.

Feb 11, 2025 / Michele Goodwin and Gregory Shaffer