Senate Judiciary Committee Chairman Edward M. Kennedy (D-Mass.) gained a key conservative ally yesterday in his effort to keep control over his controversial measure to end government-sanctioned price-fixing in the trucking industry.

Kennedy was joined by Sen. Strom Thurmond (R-S.C.) in his bid to retain jurisdiction over the matter.

At the same time, the Senate Commerce Committee voted to back chairman Howard W. Cannon (D-Nev.) in his attempt to get jurisdiction over the measure.

The devlopments are the latest in a procedural skirmish that could result in a nasty showdown on the Senate floor next week unless an agreement can be worked out for a joint referral to both committees -- something the Commerce Committee yesterday voted not to accept.

At issue is an administration-backed, industry-opposed measure that would repeal an exemption from the antitrust laws granted the trucking industry in 1948 over President Truman's veto. The exemption allows regulated trucking companies to meet privately to discuss and decide on rates they will charge shippers nationwide. The agreements are then submitted to the Interstate Commerce Commission for approval.

Both Kennedy and Cannon, who ironically teamed up to back airline deregulation after some similar tiffs, believe the measure belongs in their respective committees. Kennedy says the measure, an amendment to the antitrust laws, belongs to Judiciary. Cannon says the measure is a "transportation bill."

The Commerce action came at Cannon's initative at the committee's first meeting during this Congress. Cannon argued that the Kennedy measure could not be considered "in a vacuum" by Judiciary but should be part of an overall review of trucking regulation. In addition, he contended that Judiciary would push to get control over other measures if Kennedy wins on this measure. Cannon was backed by committee members who spoke of a Judiciary ploy to break down the jurisdictional committee lines.

While Cannon took a hard line, Kennedy yesterday maintained a conciliatory stance. Hopeful of working out some arrangement with Cannon, Kennedy yesterday postponed introducing the measure in order to have more time to seek agreement. But he also indicated he would not back off a floor vote on the issue if necessary.

In a "dear colleague" letter, Kennedy and Thurmond, ranking Republican member of the Judiciary Committee, noted that the Senate parliamentarian had indicated the proposed bill is within the Judiciary Committee's jurisdiction under Senate rules and precedents.

They insisted that the iability of existing Senate procedures for referring legislation to committees is at stake. "If fair and impartial decisions of the parliamentarian, rendered on the merits of each particular case, are not supported by members of the Senate, then the entire system of rational and impartial committee assignment is threatened," they wrote.

Kennedy and Thurmond said they did not dispute the Commerce Committee's jurisdiction over trucking deregulation because it would involve a change in government regulation of the industry, but felt the issue of private restraints of trade -- price-fixing -- belonged to Judiciary. A top Kennedy staff person said Kennedy would abide by the parliamentarian's decision if it went against him.

Connon argued yesterday that Judiclary had antitrust jurisdiction since 1946, two years before the antitrust exemption was handled by the Commerce Committee exclusively, but Kennedy staff members note there was no antitrust subcommittee until the 1950s

In addition, Kennedy staffers say, the congressional action voting the exemption was specifically designed to overturn the effects of a Supreme Court decision that found private price-fixing in the transportation industry to be illegal. Truckers had been regulated since 1935.

The trucking industry has been lobbying heavily to have the Kennedy measure referred to the Commerce Committee. "We feel that Sen. Cannon has a much more open mind on the issue," a spokesman for the American Trucking Associations said.

But some proponents of the measure feel that referral of the measure to Commerce would effectively kill it, since Cannon insists that it be considered as part of an overall trucking deregulation measure. It is believed unlikely such a bill will emerge from Ocngress during this election year-truncated Congress.

Sen Howell Heflin (D-Ala.) declined to vote during the Commerce deliberations since he also sits on the judiciary Committee.