What makes you think limiting the intruders to this country wouldn't help? How did the terrorists get into Paris? They weren't French, you know.What is wrong with you? We are allowing illegals to come in all over the place and with them will come the terrorists. Building that damn wall we have talked about for decades in the answer and deport those who break our laws.So, if we cannot stop every single person from coming in, we shouldn't close our borders to keep most of them out? If we are going to allow legal immigrants, they need to be vetted.So you really think you can stop every single person from slipping into the country? You know better than that.
It won't work. You can't guarantee that terrorists won't get in.
What made you think building a wall will stop terrorism?