Why can't law enforement (FBI, State Police) perform a wire tap at the telephone company?

eyecue is correct. Telephone switching is all computerized now. Once the police have their court order directing that the telephone number be intercepted, it's just a matter of key strokes by the telephone company to give the police the ability to listen in from whatever location they choose. When necessary, police can still--with a court order, of course, intercept oral conversations pertaining to criminal activity that take place in an office, home, or wherever. Those still require a technician to install the listening device in the area where the conversations are believe to be taking place. And that sometimes requires the police to actually break into a residence or office to make the installation. These are used only as a last resort, and only on the most serious, difficult cases, such as terrorism, mafia, or drug kingpin figures. Also, the police must demonstrate to a judge that they have exhausted all other investigative means before he will sign a court order for a wire tap or oral intercept.

It can be done legally and what it requires is known as a Title 3, which is a federal matter. They are very difficult to acquire because of the Constitution. It is an extremely complicated and time consuming issue. And to the best of my knowledge, no one has ever been 'tipped off' by a phone company employee.

The major departments like in the Federal Govt have the technology to just put the information into a computer and the computer is hooked to the phone company and it is instant. The days of breaking into a house and setting one up like you describe are not very common anymore.

It can and is done due to federal law. Also known as CALEA, Communications Assistance for Law Enforcement Act.