President Trump’s decision to impose travel restrictions on terror-prone countries has triggered a wave of media-lauded protests claiming Trump’s restrictions are anti-Muslim, or anti-Islam, or racist, or pro-fascist or pro-Nazi, or all of above.

What those who object to the so-called “unprecedented” policy of screening refugees fail to note is that, throughout the Cold War (1946-1988), the United States implemented similar entry restrictions on white, Christian, anti-socialist refugees.

The vetting process averaged two years. Candidates for visas had to prove that they were not members of the Communist Party or any communist dominated organization. Also, each and every candidate had to have a sponsor guaranteeing that the candidate will not go on welfare programs. Unlike the refugees and street protesters today, the immigrants from Eastern Europe and Russia as well as American public opinion appreciated this vetting process.

Through decades of research and interviews with them, I found that most refugees considered the entry into the United States to be a privilege rather than a right. Moreover, the refugees from communism quickly integrated into the life in America.

For example, the entire order of the Cistercian Fathers came from Hungary to Dallas in 1956. Upon receiving a piece of land from a wealthy rancher in Texas, Cistercians started a college preparatory school network, which is one of the best in the region. Throughout the cold war years, we observed no public protests against restrictions on the entry of refugees from the East and no opponents claimed travel restrictions were anti-Christian or anti- white, or anti-Russian, or anti-Polish, etc.

Entry restrictions from communist-controlled countries yesterday and those intending to curb radical Islam today have the same objective: to protect U.S. citizens from terrorism and to safeguard our formal and informal institutions from alien doctrines. Recently, Professor Borjas generalized the vetting process as follows: “…the next time you hear that Trump’s proposal for immigrant vetting [is] un-American, the correct response is that… given the mess the world is in, it is the notion that we should not vet immigrants more carefully that is certifiably insane.”

The question is then whether restrictions on the entry of refugees into the United States have been effective in meeting those objectives. The answer depends on empirical evidence. And the evidence is that the infiltration of spies and the acts of sabotage in Western Europe exceeded those in the United States during the Cold War in the 20th century and the war against radical Islam in the early 21st. One telling explanation for this difference is that the vetting process of refugees was and still is less thorough in Western Europe than in the United States.

Those who oppose vetting refugees say President Trump’s actions are unprecedented and dangerous. The history books, and the millions of Cold War refugees and their descendants happy to call America home, prove them wrong.

Svetozar Pejovich is Professor Emeritus at Texas A&M University.