“Sharia bans” violate the religion clauses of the First Amendment, which guarantee that people of all faiths (and none) can practice their religious or other traditions, so long as they respect the rights of others. Such bans also create a precedent for targeting other minority religions.
“Sharia bans” are especially detrimental for observant Jews. Jewish law (halakha) and Sharia are very similar with common standards of dress (beards and head coverings), daily formal worship, and prohibition against eating pork, circumcision, and marriage and divorce practices. Any ban on Sharia practices could impact many Jewish practices as well.
“Sharia bans” also threaten the American traditions of arbitration. Our democracy allows private parties to settle disputes out of court, following their own arbitrators (within the limits of civil law). American Jews and other groups sometimes engage in arbitration following their religious traditions. Sharia bans would make these illegal.
Finally, “Sharia bans” threaten everyone’s economic livelihood, including secular Americans. America’s economy depends on international trade. Our trade agreements and business contracts often reference the laws of other countries. “Sharia bans” would make it impossible for American courts to consider those laws when handling disputes about contracts. Foreign investors, therefore, would have less protection in American courts, which would result in decreased investment in the United States, causing our economy to suffer.