Americans of a"certain age"abound at the upper levels of American governance.President Trump is the most obvious example.Just over half of US senators wrll be 65 0r older by the end of this year.On the Supreme Court,five of rtine justices are over 65.These"senior citizens"make crucial decisions for the majority of Americans younger than them.Just eight decades ago,when the Social Security system began,65 was codified as the start of"old age".Now many people of that age may feel in the prime of life.Measured by years alone,Americans are on average getting older.A popular notion is that a war is brewing between generations-young working Americans resenting that they must pay more into SociaJ Security and Medicare to support an expanding group of older Americans.There"s truth in that sentiment.I,ast year,there were 25 people over 65 for every 100 people between 18 and 64.And the worker-to-retiree ratio is projected to be even worse by 2030.But that idea is being challenged.To begin with,programs like Social Security and Medicare can be adjusted,as ihey have in the past.while certain trends,such as Americans delaying full retirement,could alter the projections.A pair of new government reports show that funding for Medicare will run out in 2026.The Social Security trust fund will dry up by 2034.Despite these warnings,modest fixes are available,including making small changes in the age of eligibility that recognize lengthening life spans.Even that step may not be needed.By one estimate,increasing the Social Security payroll tax by 2.88 percentage points could eliminate the expected revenue shortfall for another three-quarters of a century.But actuarial tables,however useful for government planning,shouldn"t impose artificial limits on what older Americans do.Aging isn"t what it used to be.Today,75-year-olds on average will live just as many additional years as the average 65-year-old did in 1952.Categorizing by age can be just as harmful as by gender or race.Labeling people by an age category is a receiit phenomenon.The idea of being"middle aged"wasn"t popularized until after World War I.Marketing continues to classify Americans by calendar years,walling off the beneficial effects of older and younger people rubbing shoulders.Companies are beginning to consider age diversity to be as important as racial and gender diversity.Some observers suggest businesses try the"shoe test":Look under desks.If everyone"s wearing the same kind of shoes-whether wingtips or slipper-the business would benefit from more diversity.Today,suggests one expert,Americans have an opportunity to make a"fresh map of life itself",throwing off outworn ideas about aging.Policies that encourage older Americans to expand the possibilities of their"senior years"will help change limited perceptions and benefit all of society. "That sentiment"（Line 4,Para.2）refers to the concern that