>There are people who are sitting in jail right now who have pled guilty to plotting terrorist attacks that were prevented.

Well that proves it doesn't it! Except that those people were entrapped by the US government. Talked into doing attacks they'd have never actually done sans government involvement and suggestion.

The actual terrorist attacks that have been tried either worked or failed because the terrorist was incompetent. In any case, terrorism is such a minuscule cause of death or injury that there is no reason to even consider it. Just ignore it like the gnat that it is.