and someone who follows the Court closely, this was an absolute given. A lot of "observers" simply take note of the fact that there isn't a circuit split and move on. But that is a far too simplistic way of analyzing a case such as this.
It would be foolish for the justices who are sympathetic to the challenge to the law not to take the case. While the denial of certiorari technically does not carry precedential weight, as an attorney you always like it when the case you cite as support has "cert. denied" as part of the citation. Denying cert and allowing the decision upholding the law to stand isn't a message the justices who are inclined to challenge the decision would want out there (just as, if the shoe was on the other foot, we'd be freaking out if the appeal was of an adverse decision and the four justices we believe are inclined to support the law let it stand while other cases were pending).
Add to the mix the fact that this isn't a clear cut case -- that there already have been two rulings going the other way (one by a three judge panel that is currently vacated pending en banc review and one by a District Court judge). When the Court sees that there is a division, even at the District Court level, it sometimes will take a case before a second decision finishes its trip through the appellate courts. That happened earlier this year on another case I was working on.