There is a Republican tradition established for several election cycles.
The 2008 elections put on the road the hilariously disturbing McCain and Sarah Palin show and had Republican contenders out-enthusing each other on the practically irrelevant matter of torture, turning the question into a wedge issue (lest Bush era officials be prosecuted). In the 2012 campaign there was Romney vowing to double Guantanamo, just to underline that having set up this institutionalised legal limbo was a splendid idea (lest Bush era officials still be prosecuted). Republicans then went to great length suggesting that having these prisoners in a prison on US soil would spell the end of the world as we know it.
Today we have Republican aspirants express their utter horror at yet another non-issue: America being overrun by the Syrian Muslim hordes. Ben Carson demanded the US screen, thoroughly, for ‚mad dogs‘ amongst the Syrian refugees - as if DHS wasn't already. Ted Cruz, not to be outdumbed by anyone, wants to make a religious test at the border and sort out all Muslims.
It is said that further proposals – throwing the witch in the river to see if she swims, having Muslims wear green pointy hats or armbands – were met with general approval by the Republican conclave but were found to be too difficult to spell.
One could perhaps see a point to all this if there was an actual problem with Syrians in the US.
Well, there isn’t. While the US has, with Saudi-Arabia, Qatar and Turkey, done more than any other nation to destabilise Syria, the US have so far taken the not-so staggering number of 1,854 (give and take) Syrian refugees.
That is still 1,854 times as much as as Saudi Arabia has accepted, but not much more than the average German Kreis (~County) is taking. Even if the US took, as Obama has boldly suggested, 10.000 next year, they are light years away from what Europe is experiencing. Distributed over a 317 million nation, it is probably something that the US could handle easily.
The US can freely choose to take or not take these refugees because the refugees can’t just walk up to the US, as they can in Europe. That is the result of the simple fact that the US is blessed by geography and insulated from the Syrian shitstorm they very actively helped unleash by the Atlantic Ocean and the Mediterranean Sea. Syria is some 9000km away.
Some Republican candidates apparently didn’t notice yet. To the extent the others did, they wouldn’t let that get in the way of a focus-group approved talking point. So, be afraid, very afraid!