sentences:  Justice Brennan wrote a dissent that Justice Marshall joined.He found that the decision strayed from the precedent set by "Zemel" and "Kent" because neither "Zemel" nor "Kent" held that a longstanding Executive policy or construction was sufficient proof that Congress had implicitly authorized the Secretary's action.Those cases held that an administrative practice must be demonstrated; "Kent" unequivocally stated that mere construction by the Executive - no matter how longstanding and consistent - was not sufficient.