A federal judge in Texas has temporarily blocked the administration from moving forward with border-wall construction in the Big Bend region, handing challengers an important early win in a closely watched public-law dispute. Judge Kathleen Cardone concluded that the plaintiffs—who include landowners, businesses, and environmental advocates—were likely to succeed on at least one of their claims and would face irreparable harm if construction proceeded before the case could be fully heard.

That combination matters.