We’re just teaching the terrorists that we are willing to give up the 4th. That will also make it easier to go after the 2nd since illegal searches will turn up illegal large magazines and the ACLU by their own admission won’t defend those cases.
I think it's the other way around: They're teaching us that we are willing to give up our rights for the appearance of "security." Ironic, isn't it, that the Fourth Amendment specifically mentions security as its purpose.