It's not a bad idea; there's in theory a very weak such wall already present so it's not as if there's no precedent. And I'd certainly feel better knowing that

It's not a bad idea; there's in theory a very weak such wall already present so it's not as if there's no precedent. And I'd certainly feel better knowing that techniques like parallel construction could be replaced with a formal mechanism under strong oversight for use in serious criminal cases, without destroying intelligence sources and methods.