The Senate should not revise the pending arms pact with the Soviet Union to bind future administrations to the current understanding of its intent, says the State Department legal adviser. ``I don't think it is necessary or desirable to do that kind of thing,'' legal adviser Abraham D. Sofaer said in an interview. The heart of the issue is not so much a treaty signed last December banning medium-range nuclear missiles from superpower arsenals as a treaty signed in 1972 which limits testing of President Reagan's Strategic Defense Initiative missile defense system, known as Star Wars. Democratic Whip Alan Cranston of California has been holding discussions with senators from both parties, and an aide said he expects ``there to be language in the ratification resolution addressing the treaty interpretation issues.'' Cranston has predicted that the treaty will win the necessary 67 votes in the 100-member body to be ratified. Few senators have expressed disagreement over the meaning of the Intermediate-range Nuclear Forces pact signed at the Washington summit last December calling on the superpowers to destroy their nuclear missiles with ranges of 300 to 3,000 miles. The central controversy is an interpretation of the ABM pact written by Sofaer in 1985 which would allow wider testing of Star Wars components. Cranston's legislative aide, Gerry Warburg, said the language expected in the INF resolution ``would contain a more broad statement concerning the interpretation of treaties generally,'' including the ABM pact. Cranston, Sen. Sam Nunn, D-Ga., the chairman of the Armed Services Committee, and Sen. Joseph Biden, D-Del., of the Foreign Relations Committee, all oppose Sofaer's ``broad interpretation'' of the ABM pact. Warburg said they had been discussing the INF resolution with Secretary of State George P. Shultz. The senators contend that allowing the broad interpretation amounts to changing the rules in the middle of the game and would set a dangerous precedent in which any administration could duck treaty requirements simply by reinterpreting them. Sofaer said inclusion of restrictive language in a resolution ratifying the INF treaty would not be binding on the Soviet Union, and could complicate rather than resolve interpretation of the ABM pact. ``I know that they are not going to get a settlement of the ABM dispute this way,'' said Sofaer. ``It is a potential problem for INF ratification and I think overwhelmingly people support INF ratification.'' Sofaer noted that Shultz had sent the Senate the 31-volume negotiating record of the INF pact and had also agreed that any testimony by administration officials would be ``authoritative'' and reflect the president's understanding of the treaty. ``Those practical things have been achieved,'' said Sofaer, objecting to including in the ratification resolution any language that would commit future administrations to the current understanding of the treaty. ``If you want to go further, you might end up confusing or even harming international legal practice relating to treaty ratification,'' he said. While the Senate can bind the administration to a particular interpretation of either the INF or the ABM treaties, he said, it cannot bind the Soviet Union, unless the treaties are renegotiated. ``The treaty reflects two relationships,'' he said. ``It reflects a relationship between two sovereign nations, and then it also reflects the relations between the United States executive branch and the Senate. ``When you talk about the meaning of a treaty, you are talking about the international relationship. You are talking about what binds the two nations.''