Can a counterclaim that raises a federal question establish federal jurisdiction?

The assertion that a counterclaim cannot independently establish federal jurisdiction is grounded in the well-pleaded complaint rule. Essentially, this rule dictates that jurisdiction is determined by the claims stated in the plaintiff's initial complaint rather than by counterclaims or defenses raised by the defendant.

In cases where the plaintiff's claim arises under state law and the defendant raises a counterclaim that involves a federal question, the defendant cannot rely on the counterclaim to invoke federal jurisdiction. Instead, the original complaint must present a federal question itself in order for federal court to have jurisdiction. This principle ensures that just because a counterclaim introduces a federal issue, it does not independently give rise to federal jurisdiction if the plaintiff’s original claim does not.

In summary, while counterclaims can be significant in a case, they cannot establish the basis for federal jurisdiction if the initial complaint lacks a federal question, thereby making the assertion in the chosen answer that it follows the well-pleaded complaint rule accurate.