Keep them Evil foreigners out of our country?
Don't worry, none of them wanted to come.
As for your gun claims, many leftists have actually just stated that the US needs a ban on assault weapons (because they are useless in self defence yet amazing for things like, I don't know, mass shootings). Here is a tip for the US: Take a page out of Switzerland's book when it comes to gun control. They have had no mass shootings since 2001 in Switzerland, and every time they make a mistake, they (unlike America) learn from it.