SCOTUS Blog also discusses the implications of the permanence of SmithKline:
Of the twelve federal appeals courts to confront the issue, ten have taken the position that challenges to laws which allegedly discriminate on the basis of sexual orientation should be analyzed only by the least-demanding standard — that is, “rational basis” review. Using that standard, at least some courts have upheld bans on same-sex marriage.
In the cases now awaiting Ninth Circuit review, state officials are attempting to defend same-sex marriage bans only in the Idaho case. State officials in Oregon and Nevada have given up the defense of such bans, and Hawaii has moved on its own to allow such marriages. Because the panel’s decision in the SmithKline decision is now binding in that circuit, in the wake of denial of en banc review, it sets the standard for judging the state bans throughout the geographic region included in the Ninth Circuit.The other appellate court to decide sexual orientation should receive heightened scrutiny is the 2nd U.S. Circuit, which did so in their ruling which struck down the Defense of Marriage Act in Windsor v United States, a decision the Supreme Court upheld last year (but did not address the level of review question).