Friends, Some good news to end the year on. The Supreme Court today blocked Trump from sending the National Guard into the Chicago area — finally setting a limit to Trump’s executive power.

The decision was 6 to 3, with Roberts, Kavanaugh, and Barrett joining the three liberal justices in a majority. Alito, Gorsuch, and Thomas dissented.

The court said that Trump had “failed to identify a source of authority that would allow the military to execute the laws in Illinois,” and, presumably, other states. Trump had said he needed the troops to protect federal immigration agents at a detention facility.

Existing law allows a president call on the military if there is a foreign invasion or “danger of a rebellion,” or if the president is unable to execute federal laws with “regular forces.”

Trump’s Justice Department argued that “regular forces” means federal civilian law enforcement, such as Immigration and Customs Enforcement officers. And protests in Illinois prevented the president from enforcing immigration laws using ICE officers alone.

But a majority of the court found that the term “regular forces” refers to the nation’s standing military — and the authority to call the National Guard into federal service is meant as a backstop for the Army, Navy and other “regular” military forces.

The court noted that a president’s ability to use the military this way is limited to “exceptional” circumstances. That’s because another federal law, known as the Posse Comitatus Act, sharply restricts the use of the standing military to conduct domestic law enforcement.

Bingo.