Ted Cruz advocated overturning nearly 100 years of Supreme Court precedent on Wednesday.

In a speech at the Heritage Foundation in Washington D.C, the Texas senator advocated overturning the high court’s 1920 decision in Missouri v. Holland. In that case, the Court upheld as constitutional a treaty that required the federal government to enact laws regulating migratory birds after a previous statute on the subject was found unconstitutional in a lower court. In its opinion, written by Justice Oliver Wendell Holmes Jr, the Supreme Court suggested that the treaty power is broader than the Congress’s normal lawmaking power.

Cruz made the statement while discussing a case called Bond v. United States which also deals with the scope of the treaty power and will be heard by the Supreme Court on Tuesday. The Texas senator said “Missouri v. Holland, it may be possible for the court to distinguish that case. There are grounds on which you could distinguish it. But, if you can’t distinguish it, then Missouri v. Holland should be overruled.”

However, Missouri v. Holland is considered a major case, not just for its implications for the treaty clause, but because a critical passage in the court’s decision embodies the judicial philosophy of “a living Constitution.” Holmes wrote in his opinion “The case before us must be considered in the light of our whole experience and not merely in that of what was said a hundred years ago.” As a result, overturning Missouri v. Holland would be an important blow for conservatives in the broader legal wars over how to interpret the Constitution.