Donald Trump’s presidential campaign has done it again. Speaking aboard the USS Yorktown on the 74th anniversary of the Japanese attack on Pearl Harbor, Trump called on our government to stop letting Muslims enter the United States “until our country’s representatives can figure out what the hell is going on.”

Trump’s profanity was justified by the revelation that the Muslim wife who helped her Muslim husband massacre 14 people in San Bernardino received a visa from our government, which gave her official permission to enter the United States last year. With that visa and her Pakistani passport, she legally traveled from Saudi Arabia to San Bernardino and married her U.S.-born Pakistani fiancé, with whom she jointly plotted jihad against Americans.

Before Tafsheen Malik received that valuable visa from our government, she was supposed to be screened for terrorist sympathies. A week after the massacre, FBI Director James Comey told Congress he still didn’t know if she was given the required personal interview or what questions she was asked.

Now that it’s too late to keep her out, we’re learning that Tafsheen left a long trail of jihadist rants on social media which were overlooked by the U.S. consular officials who granted her visa. We learn from the New York Times that “anti-American sentiment in Pakistan was particularly high” following the raid that killed Osama bin Laden and that “it is often difficult to distinguish Islamist sentiments and those driven by political hostility toward the United States” – in other words, anti-American attitudes were not enough to keep a Pakistani Muslim out of the United States.

Other presidential candidates rushed to disavow Trump’s proposal, which they claimed was illegal, unconstitutional, or “not who we are,” echoing a sanctimonious phrase that President Obama has used 46 times.

Unconstitutional? On the contrary, the Supreme Court has never dared to limit Congress’ “plenary power” over immigration, even when it was based on race, religion or national origin. In a 1977 case, for example, the Supreme Court observed that “the power to expel or exclude aliens [is] a fundamental sovereign attribute exercised by the government’s political departments largely immune from judicial control.”

That plenary power is best expressed in this federal law: “Whenever the president finds that the entry of any aliens, or of any class of aliens, into the United States would be detrimental to the interests of the United States, he may by proclamation, and for such period as he shall deem necessary, suspend the entry of all aliens or any class of aliens as immigrants or nonimmigrants.”

That law was the work of one of our greatest U.S. Senators, Pat McCarran (D-NV), after whom the airport at Las Vegas is named. Along with Representative Francis Walter (D-PA), the two Democrats wrote the McCarran-Walter Immigration Act which Congress passed over Harry Truman’s veto in 1952.

All during the Cold War, McCarran-Walter was successfully used to keep out aliens who were members or “fellow travelers” of the Communist party or members of “Communist front” organizations. In 1980, the same law was used by President Jimmy Carter during the Iran hostage crisis to suspend visas to anyone who wanted to come here from Iran.

In addition to barring the entry of “any class of aliens” who may be “detrimental to the interests of the United States” (a category that could include Muslims or persons of any faith who are citizens of, or have traveled to, a Muslim country), the law says the president may “impose on the entry of aliens any restrictions he may deem to be appropriate.” They could be required to wear ankle bracelets to monitor their movements, or to provide passwords to their electronic devices and social media accounts, as a condition of the privilege of entering our country.

Sixty years ago, the Democratic party could boast a patriotic, pro-American anti-Communist like Pat McCarran, but that is no longer the case. Hard-left Senator Pat Leahy (D-VT) proposed an amendment, which unfortunately was adopted by the Senate Judiciary Committee with the help of seven Republicans, stating that “It is the sense of the Senate that the United States must not bar individuals from entering into the United States based on their religion, as such action would be contrary to the fundamental principles on which this Nation was founded.”

No, the fundamental principle on which this Nation was founded is that “we the people,” through our elected representatives, have the unalienable right to pick and choose whom we shall allow to enter our great country. The Constitution which our founding fathers bequeathed “to ourselves and our posterity” does not extend its rights and benefits to the whole world.