In reaction to the terrorist murders in Paris on Friday, Republican presidential hopefuls including Rand Paul (say it ain't so, Rand) are demanding that no refugees be admitted to the United States. Sen. Ted Cruz (R-Tex) claimed that letting in Syrian refugees would be a "roll of the dice." Reality TV billionaire blowhard Donald Trump declared that the refugees could be "one of the great Trojan horses." Politico reports that at least ten Republican governors are vowing to keep out of their states any of the 10,000 or so Syrian refugees that could be admitted to the U.S. next year. Just how the governors think they have the authority to prevent people who are legally in this country from going where they want is not at all clear.

So what does history say about the dangers posed by refugees? Over at the Niskanen Center, David Bier who heads up the immigration policy department provides Six Reasons to Welcome Syrian Refugees After Paris. Number 2 is most relevant to the fearmongering Republicans pols:

2. U.S. refugees don't become terrorists: The history of the U.S. refugee program demonstrates that the lengthy and extensive vetting that all refugees must undergo is an effective deterrent for terrorists. Since 1980, the U.S. has invited in millions of refugees, including hundreds of thousands from the Middle East. Not one has committed an act of terrorism in the U.S. Traditional law enforcement and security screening processes have a proven record of handling the threat from terrorist posing as refugees.

Demagoguery is the practice of a politician to gain power and popularity by arousing the emotions, passions, and prejudices of the people. For shame!

Note: Several commenters suggested Tamerlan and Dzhokar Tsarnaev, who committed the Boston Marathon bombing in 2013, were refugees. Strictly speaking, they were the children of asylees. As Bloomberg News explained the two were given "derivative asylum status" and didn't come through the refugee admissions program. Apparently the legal distinction is too fine a point for some readers. So be it, but they should nevertheless keep in mind that the brothers were two people out around 1.8 million people who were granted refugee or asylee status between 1995 and 2013.

Update: Readers might want to see the data on refugees and terrorism in my new article, "Refugees and the Risk of 'Sleeper' Terrorists."