CBS News Correspondent Teri Okita reports the PGA says Martin is getting an unfair advantage by riding. Martin disagrees.
The PGA Tour's lawyer asked the justices to rule that the 1990 Americans with Disabilities Act does not require the tour to waive its requirement that players walk the course during tournaments. Pro sports have the right to set their own rules, lawyer H. Bartow Farr III said.
But Martin's lawyer, Roy L. Reardon, contended walking is not fundamental to the game of golf making the shots is what counts.
"All that proves is that you could play golf under different rules," responded Justice Antonin Scalia. "Is it essential to the game of baseball that the pitcher bat? Is it fundamental to baseball that the strike zone be from the shoulders to the knees?"
Farr said a federal appeals court that ruled in Martin's favor "never really came to grips with what professional athletes are."
"The tour has always required that all competitors observe the same rules, including the walking rule," Farr said.
Golfers can sometimes walk 25 miles during a tournament, the PGA says, adding that fatigue may, and frequently does, affect golfers' concentration and overall performance.
The justices are expected by July to issue a ruling that could clarify how the disability-rights law affects pro sports.
At issue is the 1990 ADA's ban on discrimination against the disabled in public accommodations, including golf courses and entertainment sites. The law requires "reasonable modifications" for disabled people unless such changes would fundamentally alter the nature of the place or event.
The law's aim is to "give people like Casey Martin a chance to get to the game," Reardon said. Deferring to the PGA Tour's walking rule would give it "a free pass out of the Americans With Disabilities Act," he added.
Justice Stephen G. Breyer asked Reardon who should decide whether a sports rule is fundamental to the game. If a rule is not fundamental, Justice Ruth Bader Ginsburg asked, "Who is the judge of whether a person is sufficiently disabled to get a dispensation from a non-fundamental requirement?"
The hour-long argument had its moments of levity. Scalia said that if some justices seemed to know as little about baseball as they did about golf, "the former would be a much greater sin."
"Wait a minute," interjected Justice Sandra Day O'Connor, a longtime golfer who shot a hole-in-one last month.
"In dissent again," added Justice John Paul Stevens as the courtroom audience began to laugh.
Farr argued that PGA Tour events should not be considered public accommodations for te players. Instead, they should be considered independently contracted employees, he said.
Several justices questioned that assertion. Justice Anthony M. Kennedy said the golf tour appeared to be a public accommodation because "it's open to golfers from all over the world."
Clinton administration lawyer Barbara Underwood argued in Martin's support, saying the disabilities law was intended to sweep broadly. It would protect gamblers at casinos and exhibitors at craft fairs even if they earned their living through those activities, she said.
A federal judge and the 9th U.S. Circuit Court of Appeals ruled for Martin, saying that using a cart would not give him an unfair advantage over his competitors.
But Indiana golfer Ford Olinger lost a similar case before a Chicago-based federal appeals court. He sued the U.S. Golf Association for the right to use a cart during U.S. Open qualifying, but the appeals court decided that would change the nature of competition.
©MMI Viacom Internet Services Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report