Oklahoma "Sharia Law Amendment"

The election on Tuesday brought the approval of an interesting amendment to the Oklahoma constitution.

State Question 755 passed with an overwhelming majority of support from Oklahomans (70%-30%). The pertinent text reads:

It forbids courts from considering or using international law. It forbids courts from considering or using Sharia Law.
Already, the radical Council on American-Islamic Relations (CAIR) is challenging the new provision of the Oklahoma constitution as violative of the Federal constitution, under the Free Exercise and Establishment clauses of the First Amendment. And they may be right on the substance, although their characterization of the injury ("the knowledge that Oklahoma condemns his faith") in the brief demonstrates that standing will be a huge issue in this particular challenge.

Set the religion issue aside: can you think of any other laws that prohibit a judge from "considering" certain classes of law? For classical liberals who consider that institutions and legal process matter, such a popular measure limiting the scope of what a judge may or may not consider seems a usurpation of the judicial function.

Heck, even Justice Scalia "considers" international law from time to time, especially when he is railing against it! Would a judge in Oklahoma state court be prevented from making second-order judgments about whether international law is the proper subject of discourse?

For that matter, what if someone filed to enforce this provision in OK state court? Would a judge be prohibited from discussing "what it means to consider international law" in defining the contours of the new amendment? By its very nature, the provision seems unenforceable, even if it turns out to be in line with the Federal Constitution.