4. National Security Letters need prior judicial review and should never be accompanied by a perpetual gag order.

See also 18 USC 2705(b):

A governmental entity acting under [18 USC 2703(d)] [...] may apply to a court for an order commanding a provider of electronic communications service or remote computing service to whom a warrant, subpoena, or court order is directed, for such period as the court deems appropriate, not to notify any other person of the existence of the warrant, subpoena, or court order.

Note that 18 USC 2703 and 18 USC 2705 were part of the Electronic Communications Privacy Act of 1986.