The refusal left in place a ruling from the 9th Circuit Court of Appeals that called the mandatory waiting period a "reasonable safety precaution".
Seventeen people were killed and more than a dozen others injured last week at a high school in Parkland, Fla.
It's well-known that Supreme Court justice Clarence Thomas often stakes out positions distinctly to the right of his fellow conservatives on the Court, and that he's significantly wordier in dissents than in majority or concurrent opinions.
In an unsigned order, the court let stand a ruling upholding California's law mandating a 10-day waiting period and another imposing fees on firearm transactions to fund background checks. "And the lower courts seem to have gotten the message", Thomas added.
The court denied a petition for certiorari [text, PDF] filed by two California plaintiffs in conjunction with the Second Amendment Foundation and the Calguns Foundation [advocacy websites] in October.
Thomas, Justice Samuel Alito Jr., and the late Justice Antonin Scalia had dissented many times from the high court's denials of review in Second Amendment cases since the landmark 2008 decision in District of Columbia v. Heller.
He's not just blaming the Court's progressive wing, by the way; he wants people to understand that it takes only four justices to agree to take an appeal from a circuit-court decision like the one in the current gun case. Purporting to apply intermediate scrutiny, the Court of Appeals upheld California's 10-day waiting period for firearms based exclusively on its own "common sense".
He said that California made no "attempt to defend a 10-day waiting period", and noted that the background-check process creates a natural 24-hour waiting period for 80 percent of purchasers.
The states of California, Hawaii, Rhode Island, Illinois, Minnesota, Florida, Iowa, Maryland and New Jersey as well as Washington, D.C., have waiting periods that vary in duration and type of firearm, according to the Giffords Law Center to Prevent Gun Violence gun control advocacy group.
That argument prevailed before the the U.S. District Court for the Eastern District of California, which ruled against the 10-day waiting period in the context of "previous purchasers".
The case is Silvester v. Becerra. As apparent examples of rights without a constitutional basis, he cited Ninth Circuit rulings on same-sex marriage - later upheld by the Supreme Court - and abortion. Since those two decisions, however, the Court has said very little about the Second Amendment.