Donald Trump’s approach to immigration, the central issue of his campaign, has frequently been thoughtless. But he is right to ask whether America’s immigration policy is promoting American security, and key elements of his immigration-focused speech on Monday afternoon, responding to Sunday’s terrorist attack in Orlando, should be common sense for American policymakers.

Over the past year, 68 people have been killed by Islamic terrorists on American soil. Two of the killers were immigrants, two were the children of immigrants. When Trump says we are “importing radical Islamic terrorism,” he is right. That is a product of security failures and sheer numbers. Every year, the United States admits approximately 100,000 Muslim immigrants (double the number we accepted in 1992) through normal legal channels, including tens of thousands of refugees from the Middle East and Africa. As Trump noted, Muslim immigrants have a tendency to form enclaves that facilitate radicalization — for example, the Somali enclave in Minnesota’s Twin Cities, which is home to dozens of young men and women who have traveled overseas to join the Islamic State, al-Shabaab, and other terrorist outfits.

The large numbers of Middle Eastern immigrants have strained what was already a struggling immigration apparatus. The president of the National Citizenship and Immigration Services Council, the U.S. Citizenship and Immigration Services’ union, has called America’s immigration system the world’s “visa clearinghouse”; applications are processed with an emphasis on speed, not accuracy or security. Tashfeen Malik, one of the perpetrators of the San Bernardino attack, entered the U.S. on a K-1 fiancée visa. Trump is right to note these serious failures.