In response to the latest terrorist atrocity, Newt Gingrich, the former speaker of the House, and quite possibly the next secretary of state, suggested that the U.S. should investigate American Muslims to ascertain their level of commitment to sharia, or Islamic law. (Details about the attacker, and his motives, were still emerging as of Friday morning; police sources have said the attacker was a young French Tunisian, though at press time there was no official confirmation.) “Western civilization is in a war. We should frankly test every person here who is of a Muslim background, and if they believe in sharia, they should be deported,” Gingrich told Fox’s Sean Hannity. “Sharia is incompatible with Western civilization. Modern Muslims who have given up sharia, glad to have them as citizens. Perfectly happy to have them next door.”

There are a number of problems with the timing and content of Gingrich’s statement. At a moment when the world—and by “world,” I mean all non-Muslims and Muslims who reject the ideology of ISIS and the theology of radical Islamism—should be united in its defense of enlightened civilization, Gingrich, and others like him, do ISIS a favor by making Islam itself the culprit. The war we are experiencing is not primarily a war between civilizations, but a war within a civilization. ISIS, and its fellow travelers, will ultimately be defeated only by Muslims themselves, including Muslims who adhere to Islamic law. Muslims who meet with ISIS disapproval—which is to say, most Muslims—are the constant targets of murderous Islamists. The countries that are fighting ISIS include several Muslim-led, Muslim-majority states, and include states that are governed by Islamic law. Among other goals, ISIS seeks to convince devout Muslims that there is no place for them in the West. Suggestions like Gingrich’s reinforce this core ISIS message.

And about this sharia that Gingrich finds so outrageous:  Sharia, in many ways, is analogous to Jewish law, or “halacha.” (Both words mean, more or less, “the way,” or “the pathway.”) There are several schools of sharia thought, that range from fundamentalist to liberal in approach. The conservative, Hanbali, interpretation, when stringently applied in matters of punishment for criminal and sexual transgressions, is very harsh by Western standards, but sharia, as Muslims understand the term, is not merely about punishment. Islam, like Judaism, is a law-based religion, and Islamic law concerns itself with all aspects of human existence: from marriage and divorce to economics and commercial law to personal behavior and hygiene. To attack “sharia” so broadly is to offend Muslims who are also offended by ISIS and repulsed by the sort of jihadist terrorism afflicting much of the world today.

There is much to critique in Gingrich’s approach, but I was struck in particular by his statement that “Sharia is incompatible with Western civilization.” One of the Middle East countries that officially endorses sharia as a legal system is one of Gingrich’s most favored countries, Israel, which is, by his lights—and mine—a crucial component of Western civilization. Israel’s sharia courts, which are supervised by the Ministry of Justice, allow the more than 15 percent of Israel’s population that is Muslim to seek religious recourse for their personal dilemmas. These courts have been in operation since Israel’s founding, and yet the country does not seem to have been fatally undermined by their existence. Israel’s sharia courts raise complicated mosque-state questions (and the power of the Israeli rabbinate raises complicated synagogue-state questions) but, so far, Western civilization, in its Israeli democratic manifestation, seems to be holding on.

So, apart from the obviously unconstitutional quality of Gingrich’s demand—and its deeply counterproductive national security component—another question is worth raising: Does the Israeli government’s support for the existence of sharia courts—the government actually pays the salaries of sharia judges—cast doubt on the Jewish state’s commitment to Western values? Should Benjamin Netanyahu, the Israeli prime minister, be questioned by American authorities for advancing the cause of sharia? And what about Israel’s president, Reuven Rivlin, who, in a recent ceremony welcoming the appointment of seven new Muslim court judges, quoted the following passage from the Quran: “Indeed, did We send Our apostles with all evidence of truth, and through them We bestowed revelation from on high, and gave you a balance so that men might behave with equity.”

For the sake of consistency, if nothing else, Gingrich ought to call for the investigation of these sharia-supporting Israelis.