This time, they are taking aim at a 5-4 ruling from earlier this year that changed a long-standing interpretation of age discrimination laws. The court said workers must show age was the decisive factor in a demotion or layoff.
Previously, older workers had to show only that age was one factor in the employment decision.
Iowa Sen. Tom Harkin is sponsoring a bill that would have the effect of reversing the ruling.
Earlier this year, Congress passed a measure that gives workers more time to take their pay discrimination cases to court. That measure effectively reversed a 2007 Supreme Court decision that said workers had only 180 days to file pay-discrimination lawsuits.