When an ISIS-supporting Muslim named Mateen massacred 49 people at a nightclub in Orlando on June 12, Donald Trump reminded Americans that he is still the only political candidate to support a pause in the massive flow of Muslims entering the United States. Trump made his proposal last December after another ISIS-supporting Muslim massacred 14 people at an office Christmas party in San Bernardino, California.

Trump said his Muslim ban would be temporary. “Until we are able to determine and understand this problem and the dangerous threat it poses,” he said, “our country cannot be the victims of horrendous attacks by people that believe only in Jihad.”

Trump’s reasonable, commonsense proposal was immediately condemned or disavowed by other presidential candidates in both parties. Even Senator Ted Cruz said he disagreed with it, though he didn’t say why.

Now that Cruz has returned to his “day job” as U.S. Senator from Texas, he recently co-authored a new report with Senator Jeff Sessions that provides powerful support for Trump’s position. The report issued June 22 shows that the overwhelming majority of convicted terrorists came into our country as immigrants or refugees from Muslim countries.

Cruz and Sessions were able to determine the birthplace of 451 of the 580 individuals who were convicted of terrorism since the 9/11 attacks on September 11, 2001. Some 380 of the 451, or 84% of these terrorists, were foreign born – and most of them came from Muslim-majority countries such Pakistan, Egypt, Lebanon, Yemen, Somalia, Iraq and Afghanistan.

Of the 71 terrorists who were born here, most were children of immigrants or refugees from Muslim countries, although the Senators could not report the exact number because the Obama administration refused to provide that information. Despite four official letters from the U.S. Senators on August 12, December 3, January 11, and June 14 to the appropriate agencies of the U.S. government, Obama’s appointees have refused to answer questions about the immigration status of the 580 persons convicted of terrorism in the United States since 9/11.

Coming six months after San Bernardino, the Orlando massacre entitled Donald Trump to say “I told you so” and he did so in a powerful speech on June 13. “We admit more than 100,000 lifetime migrants from the Middle East each year,” Trump said. “Since 9/11, hundreds of migrants and their children have been implicated in terrorism in the United States.”

Trump was right to include the children of immigrants as part of the immigration problem. The Orlando shooter Mateen was born in the United States, but a witness said he referred to Afghanistan as “my country.”

Besides Orlando, other mass killings have been perpetrated by the U.S.-born children of Muslim immigrants or individuals who were brought here as children by their Muslim parents. Examples include one of the San Bernardino killers; the Fort Hood shooter, Major Nidal Hasan; the Tsarnaev brothers, who bombed the Boston Marathon in 2013; and the man who killed four active-duty Marines and a sailor in Chattanooga in 2015.

Don’t overlook the Muslims who entered the United States on the pretext of marriage, such as the Pakistani woman named Malik who helped her husband commit the San Bernardino massacre. The Orlando shooter’s first wife, his second wife, and his second wife’s first husband were all Muslims who never should have been allowed to come here.

In an interview, Trump said “there’s no real assimilation” by Muslim immigrants, even in the “second and third generation.” A liberal website called Politifact tried to refute that statement by citing a telephone survey of Muslims who said they wanted to become American, but the interviews were conducted in “Arabic, Farsi and Urdu” – hardly evidence of assimilation.

Other countries have recently experienced terrorist massacres directed or inspired by the Islamic State, including 130 murdered in Paris; 32 in Brussels; 45 at the airport in Istanbul, Turkey; 28 at a restaurant in Dhaka, Bangladesh; and, most recently, 200 in Baghdad, Iraq. Obviously we can’t prevent atrocities in other countries, but we can and should prevent potential terrorists from coming here.

Obama, however, is doing just the opposite. He has admitted over 5,000 so-called refugees from Syria this fiscal year and scattered them to 167 communities in 39 states. More than 99% of the Syrian refugees are Sunni Muslims, and only 8 individuals identified themselves as Christian. The Obama “surge” of Syrian refugees is on track to reach 10,000 by September, even though FBI Director James Comey told Congress last year that there’s no way to vet them adequately.

Most Syrians lack the skills to support themselves without government assistance, and Robert Rector of the Heritage Foundation calculates that 10,000 refugees will cost federal, state and local taxpayers some $6.5 billion over their lifetime. If that’s not bad enough, Hillary Clinton has vowed to increase the number of Syrian refugees to 65,000.