So what if a federal law was adopted outlawing the use of arbitration based on religious law?
Then you'd outlaw arbitration based on religious law. Of course, you have to ask yourself, what are the unintended consequences of that. You would, for a variety of industries, make it harder for US companies to do business with some foreign companies.
With near double-digit unemployment, the last thing we need to do is erect more barriers to commerce and trade.