New Mexico v. Texas

Background

The State of New Mexico asked the Court to reconsider an earlier December 5, 1927 opinion. The petition showed that some statements in that opinion about prior recognition of the boundary by Texas and the United States were inaccurate. The Court reviewed the evidence and agreed a correction was needed even though the earlier error did not change the final outcome.

Reasoning

The Court denied New Mexico’s petition for rehearing but modified its earlier opinion. It ordered specific sentences and a paragraph removed and substituted new wording taken from New Mexico’s Constitution. The substituted text describes the State’s boundary as running along the thirty-second parallel to the Rio Grande “as it existed on the ninth day of September, one thousand eight hundred and fifty,” then following the river’s main channel to latitude thirty-one degrees, forty-seven minutes north. The United States confirmed that description by admitting New Mexico with that boundary, and Texas has affirmed the same in its pleadings in this case.

Real world impact

The change corrects the official opinion’s factual record and clarifies the precise boundary language relied on in the case. The correction does not alter the case’s ultimate decision, but it clarifies which historical river channel and constitutional description define the New Mexico–Texas boundary. The Court’s order, therefore, both denies rehearing and preserves the final result while improving the opinion’s accuracy.