Washington ? Note to lawyers: It’s probably best not to bring up the infirmities of the elderly when arguing an age discrimination case before the white-haired members of the Supreme Court.

Attorney Glen Nager tried it and got a cold reception Wednesday as justices debated standards for on-the-job age discrimination lawsuits. The stakes in the case are huge for businesses, because a loss in the case would open them up to more lawsuits when layoffs or other cutbacks hurt older workers.

Nager, in asking the court to limit lawsuits, said age discrimination claims were different from race and gender bias cases. Treading not so gingerly, he told the court, “It’s painful,” considering justices’ ages, to point out that older employees have different mental and physical abilities.

The justices, whose average age is 70, seemed unamused. Justice Ruth Bader Ginsburg reminded the Washington lawyer that artists like the composer Giuseppe Verdi did their best work in their 70s.

The court members have lifetime appointments and total job security. Many of them appeared concerned about shutting courts to people penalized at work because of their age.

The case is particularly important because the work force is aging. About half of all employees in the country, more than 70 million people, are over 40 and protected by a 1967 anti-discrimination law.

It’s clear that the law lets them sue employers and win if they can prove they were targeted for a firing, demotion or other employment action because of their age.

That standard can be hard to meet, however, because of the lack of a paper trail or other evidence.

At issue Wednesday was a more subtle form of discrimination — when job policies that appear neutral actually have a disproportionately harsh effect on older workers. Some lower courts allow so-called disparate impact claims under the 1967 law. Others don’t.

The Supreme Court already has said such lawsuits are allowed under the 1964 Civil Rights Act, which bans discrimination based on a worker’s sex, religion or race. Justice Antonin Scalia said Wednesday that Congress used the same language in both laws. “It seems to me they wanted the two to mean the same,” he said.

Justice Stephen Breyer said the law forced employers to think about age discrimination before imposing new rules that would affect them.

“My clients do think about this problem,” responded Nager, who represents the city of Jackson, Miss., in this case. He said employers made many age-related business decisions and should not be constantly threatened with lawsuits.

The justices are reviewing a case involving Jackson police officers who sued the city when their younger colleagues got more generous pay raises.