The campaign to win Senate approval of the Panama Canal treaties was given a severe jolt yesterday by disclosure of a document indicating that Panama does not recognize U.S. claims to future military rights in the canal.

A confidential State Department cable made public by Sen. Bob Dole (R.-Kan.) revealed what appear to be major differences in U.S. and Panamanian interpretations of the treaties' provisions for defending the canal.

These provisions refer to the period after the year 2000, when the treaties would transfer control of the canal to Panama. At issue are questions of whether the United States will have the right to intervene militarily against threats to the canal and a right of priority passage for U.S. warships in time of national emergency.

These questions have become cruscial to the Carter administration's quest for the 67 votes - two-thirds of the Senate - necessary to get the pacts approved by that badly divided body. Several uncommitted senators have said their votes will depend on whether they are convinced that the treaties secure these rights for the United States.

In testimony last week before the Senate Foreign Relations Committee, Secretary of State Cyrus R. Vance and the two U.S. treaty negotiators, Ellsworth Bunker and Sol. M. Linowitz said repeatedly that those rights are safeguarded by the language of the treaties.

Specifically they said that treaty language pledging the United States and Panama "to maintain the regime of neutrality" over the canal gives Washington a permanent right of antervention if it considers the canal threatened.

They also asserted that the provisions calling for expeditious passage" for U.S. vessels in wartime mean that American ships would "go to the head of the line." The U.S. intrepretation of these provisions was fully understood by the Panamanian government, they added.

However, their testimony seemed to be contradicted by the cable released by Dole. It was a message sent to the State Department last week by Ray Gonzalez, deputy chief of the U.S. embassy in Panama. It reported a conversation between the embassy's political counselor and Carlos Lopez Guevara, one of the Panamanian treaty negotiators.

The cable describes Lopez Guevara as being disturbed by Vance's testimony about U.S. intervention rights, and quotes him as saying: "Intervention is simply forbidden by international law. Panama cannot agree to the right of the United States to intervene."

Lopez Guevara also is quoted in the cable as taking exception to statements by Vance and other U.S. officials that Panama's military ruler, Gen. Omar Torrijos, tacitly recognized U.S. intervention rights when he said at the treaty-signing ceremonies that the agreements could place Panama under the defense umbrella of the Pentagon.

The cable quoted Lopez Guevara as saying that U.S. officials "had made too much of Gen. Torrijos' statement . . . The general was stating a fact not giving the United States any right to intervene."

On the question of what the expeditious passage" clause means, the cable said Lopez Guevara disagreed that it allows U.S. ships to "go to the head of the line." He is quoted as saying that Panama tentatively had accepted the idea of preferential treatment for U.S. vessels early in the negotiations, but later had rejected it specifically in favor of the word "expeditious."

The cable concluded by warning Washington: "We are likely to be faced with increasing irritation over - and perhaps public disavowals of - our interpretations. Any assertion which seems to claim a right to intervene in Panama's domestic affairs is almost certain to be challenged here."

That referred to the fact that the treaties have extremely sensitive domestic political implications in Panama as well as in the United States. State Department officials say privately that the language of the neutrality clause and other touchy points was deliberately left vague by both sides to protest the Torrijos regime from charges within Panama that it had surrendered too much to the United States.

However, that has also enabled the treaties' foes in the United States to seize on these ambiguities and charge that the language of the pacts does not spell out sufficient safeguards for vital U.S. interests.

In hammering at this theme, the American critics have been aided by statements of high Panamanian officials - of which Lopez Guevara's remarks are the latest example - that appear to contradict Vance's assurances directly.

That prompted several senators to warn Vance that the treaties' chances of getting past the Senate would be jeopardized unless the divergences in interpretation are clarified. Several said yesterday that the Lopez Guevara statements are further proof of the need to establish that Panama's understanding of the treatie's conforms to that stated by the Carter administration.

That, some senators suggested, could be done by a public statement from the Torrijos government or by the Senate attaching legally binding amendments or reservations to the treaty.

Although they have promised to seek clarification. State Department officials privately express unhappiness about both ideas. Torrijos, they note, would find it very difficult from a domestic political standpoint to come out publicly in agreement with the U.S. interpretations; and any amending of the treaties by the Senate would require reopening the negotiations to obtain Panama's consnet.

The State Department confirmed the existence of the cable, and issued a statement saying: "We are assessing the effects of all these statements in a light of the treaty language and a statement of Gen. Omar Torrijos when the treaties were signed on Sept. 7, with the view to determining whether further clarification may be required."