In the 19th century, Catholicism was regarded by many people in this country as thoroughly incompatible with Americanism. They saw it as a hostile foreign element that would subvert democracy. Today, a majority of the justices on the Supreme Court are Catholic, and they are taken to be as American as Mountain Dew.

We've come a long way in religious tolerance. Or maybe not. The belief that Catholics are irredeemably alien and disloyal has given way to the fear that Muslims pose a mortal threat to our way of life.

That distrust is behind a push in state legislatures to forbid courts from applying Islamic Shariah law in any case. Arizona, Tennessee, Louisiana and Oklahoma have passed these bans, though the Oklahoma law was ruled unconstitutional by a federal appeals court.

In May, Kansas enacted its version, which doesn't mention Shariah but prohibits state courts from basing decisions on any foreign laws or other legal codes. The point, however, is not in doubt. One supporter said the bill, which passed 122-0 in the House of Representatives, was needed because "they stone women to death in countries that have Shariah law."

Does that mean we need anti-Shariah laws to keep women from being stoned to death with the cheerful blessing of American courts? Amazingly, no. It seems that our laws and Constitution take precedence on American soil no matter what the rules are in Iran.

The chief sponsor, Republican Rep. Peggy Mast, explained, "I want to make sure people understand there's sometimes a conflict between other laws and the Constitution, and we need to assert our Constitution is still the law of the land." That's like asserting that the sun is hot: It will be true regardless.

The change will have about as much effect in Kansas as a ban on indoor co-ed field hockey. It turns out no one has been able to find a case where a Kansas court has actually employed Islamic strictures to reach a verdict.

If, for instance, a Muslim man marries a Muslim woman and then tries to divorce her by saying "I divorce you" three times, in accordance with Shariah, he will find he's wasted his breath. State marriage law will govern in Kansas just as it has in other states when it conflicts with the dictates of Islam.

The problem with banning any consideration of Islamic law is that it interferes with the religious rights of Americans. If two Jewish merchants have a contract that calls for arbitration of disputes in a rabbinical court, state courts will generally enforce any judgment.

If a Muslim-owned company wants to lend or borrow money in accordance with the Islamic ban on interest, its choice should likewise be respected. If a Muslim wants to allocate his estate according to Islamic rules, what's it to you? Outlawing such accommodation for Islam would illegally discriminate against one religion.

That problem is what led a federal appeals court to overturn the Oklahoma ban, overwhelmingly approved by voters in 2010 as an amendment to the state constitution. The measure was a drone missile targeted specifically at Islam, in brazen defiance of the First Amendment.

In Kansas, by contrast, the lawmakers were so careful to avoid that pitfall that they largely defanged the measure. A decision resting on the application of foreign or other legal codes would be invalid only if the verdict violates "the fundamental liberties, rights and privileges granted under the United States and Kansas constitutions" -- something courts generally are not allowed to do anyway.

University of Virginia law professor Douglas Laycock, who generally disapproves of anti-Shariah measures, says the Kansas law "is so narrowed and watered-down it doesn't look to me like a very big deal." It's not impossible that it would prevent a court ruling, he says, but "it would be unusual."

Even so, the laws are based on fears that are unwarranted, if not fraudulent. Muslims, who make up a tiny percentage of the population, are not about to seize control of American law. The same conservatives who accuse judges of trying to stamp out expressions of Christian faith now imagine they are eager to do the bidding of ayatollahs.

Of course, it's always possible that people practicing a religion with many dark associations will bide their time, infiltrate our institutions and someday put us under the control of secretive foreign clerics. Those Catholics may be sneakier than you think.