Justice Clarence Thomas admonished the Supreme Court after its decision not to issue a stay on Alabama's gay marriage ruling on Monday.
The court declined to postpone the enforcement of the lower court's decision, a move that Justice Thomas called a mistake.
"This acquiescence may well be seen as a signal of the court's intended resolution of that question," he wrote, alluding to the court's upcoming ruling on the legality of gay marriage bans.
"This is not the proper way and it is indecorous for this court to pretend that it is," he said.
Customarily, the court issues a stay on a lower court's decision when the same issue is pending at the constitutional level.
Justice Thomas, joined by Justice Antonin Scalia, accused his colleagues of looking "the other way as yet another federal district judge casts aside state laws."
The Supreme Court is expected to rule on the constitutionality of gay marriage bans in the coming months, and many legal experts saw Monday's decision as an indication of the court's next move.
"If you read the tea leaves the Supreme Court is leaving, the bans on same-sex marriage can't be permitted. They're unconstitutional," University of California-Berkeley law professor Jesse Choper explained.
Alabama's gay marriage ban was deemed unconstitutional by US District Judge Callie Granade last month.
The red state is now the 37th in the country to allow same-sex marriages. Lawsuits questioning the constitutionality of gay marriage bans are pending in the remaining 13 states.