Contracts are not necessarily permanently binding on the signatory parties. Since international obligations are traditionally considered only on the basis of the consent of States, many treaties expressly allow a State to withdraw as long as it follows certain notification procedures. For example, the Single Convention on Narcotic Drugs provides for the termination of the contract when, as a result of denunciations, the number of parties falls below 40. Many contracts expressly prohibit withdrawal. Article 56 of the Vienna Convention on the Law of Treaties provides that, where a treaty remains silent as to whether or not it can be terminated, there is a rebuttable presumption that it cannot be terminated unilaterally, except: international law did not originally accept contractual reservations and rejected them, unless all parties accept the same reservations. In India, the subjects are divided into three lists: the Union, the State and at the same time. Under the normal legislative procedure, matters on the trade union list must be settled by the Indian Parliament. For matters on the national list, only the legislator of the Land concerned may legislate. .