number of States, making it unalterable by Congress except through the amending process again. Opponents argued that Congress, having by a two-thirds vote sent the amendment and its authorizing resolution to the states, had put the matter beyond changing by passage of a simple resolution, that states had either acted upon the entire package or at least that they had or could have acted affirmatively upon the promise of Congress that if the amendment had not been ratified within the prescribed period it would expire and their assent would not be compelled for longer than they had intended. In 1981, the United States District Court for the District of Idaho, however, found that Congress did not have the authority to extend the deadline, even when only contained within the proposing joint resolution's resolving clause. The Supreme Court had decided to take up the case, bypassing the Court of Appeals, but before they could hear the case, the extended period granted by Congress had been exhausted without the necessary number of states, thus rendering the case moot. Constitutional clauses shielded from amendment Article V also contains two statements that shield the subject matter of certain constitutional clauses from being amended. The first of the two is obsolete due to an attached sunset provision. Absolutely not amendable until 1808 were Article I, Section 9, Clause 1, which prevented Congress from passing any law that would restrict the importation of slaves prior to 1808, and Article I, Section 9, Clause 4, a declaration that direct taxes must be apportioned according to state populations, as described in Article I, Section 2, Clause 3. The second prohibition was not given an expiration date and remains in effect. It expressly provides that no amendment shall deprive a state of its equal suffrage (representation) in the Senate, as described in Article I, Section 3, Clause 1, without that state's consent. Designed to seal two compromises reached between delegates to the Constitutional Convention after contentious debates, these are the only explicitly entrenched provisions of the Constitution. The guarantee of equal suffrage in the Senate is arguably subject to being amended through the procedures outlined within the Article. Law professor George Mader holds that the shielding provision can be amended because it is not "self-entrenched," meaning that it does not contain a provision preventing its own amendment. Thus, under Mader's argument, a two-step amendment process could repeal the provision