1) Precheck still sends you through the metal detector / scanner and still X-rays all your stuff. It's probably 99% as effective in that that regard.
2) The background check they do probably makes it more secure than a normal screening. What the chances that a cornfed, midwestern woman who likes baseball, cherrypie, and is crazy 'bout Elvis tries to hijack a flight?
In fact that sort of scrutiny is how Israel does their airport security. The reason America doesn't is because giving the fifth degree to [muslims/political radicals/other ethnic groups] is illegal and unpopular.
Why wouldn't they? A large majority of terrorists end up having no prior record. It's not like a background check goes and talks to family or friends, checks references, etc (a SSBI will but a regular background check does not). A regular background check is almost entirely useless.
2) The background check they do probably makes it more secure than a normal screening. What the chances that a cornfed, midwestern woman who likes baseball, cherrypie, and is crazy 'bout Elvis tries to hijack a flight?
In fact that sort of scrutiny is how Israel does their airport security. The reason America doesn't is because giving the fifth degree to [muslims/political radicals/other ethnic groups] is illegal and unpopular.
A terrorist wouldn't apply to precheck.