This is sort of a composition/division problem, there is no relation to the Irish people of that time and Muslim nations. While they might be similar at first glance, the Irish weren't party to jihads or suicide attacks like this. Those Irish weren't seeking the destruction of the west, they were just hungry. Again, I think there is nothing wrong with caution and certainly it is warranted. Most of my direct ancestors were involved in that situation, and mostly they were just seeking a fresh start. They came to America, and wanted to live like Americans -- all of them became Americans.
Muslims are Muslims before they are anything else... They don't integrate, they don't care about anyone else, and certainly they aren't going to become Americans just because they sat here. That's predominately why I've been against bringing them in, not for any prejudice against them. When someone has that type of logic there is just no damn middle ground... If there was this argument would be over already.