Beware the new ultimate good in American life: juniority.

UNDERGIRDING the American dream of upward mobility is the notion of seniority. You train, you work hard, you make sacrifices - and then come the rewards of a wage peak, respect, authority and the sunny uplands of late middle age.

But consider all the ways in which this ideal of seniority is under attack. Unions, which enshrine the idea in hiring practices, are declining. Tenure is phasing out of our universities and will be brought under attack at public schools as outcome-based testing bites down. We have eroded the seniority system in Congress. Term limits at the state and local level undermine longevity in office. The Supreme Court has just told doting grandmas to stay away from grandchildren.

Moreover, the new economy defines the older worker as an impediment to productivity. The workplace is now ideally young, favoring fast reflexes, adeptness with technology and an ability to work huge hours. The dot-coms diss tradition and are impatient with experience (which all has to be unlearned). A friend who works at Amazon.com and is in his 40s says he feels terribly old. He astonishes his colleagues by telling them he lived in Seattle "before I-5." Soon, of course, he'll be rich enough to do the right thing and get out of the way.

What we have is a whole new ultimate good in American life: juniority.

Maybe it began with Bill Gates, who toppled big old IBM to assert the privileges of upstart youth, enshrined a workstyle that is just like dorm life on campus and made the Sudden Early Wealth Syndrome into an expected norm. Now, of course, Chairman Bill is awkwardly in his 40s, so the gods of the new order are splitting up his company and nudging him out of the top job.

The new economy that Gates midwifed creates a cultural divide between the young workers, who are getting all the money, and the older boomers, who are getting the pink slips. Productivity calls the shots in a globalized economy, resulting in many employees (about 30 percent) who now work without contracts, security, many benefits, pension plans or seniority ladders. Lacking juniority, 50-year-old executives are "right-sized" out of expensive, perk-rich jobs and replaced by younger workers who exchange permanence for the chance of striking gold in the option lode.

"In another kind of labor market, this would be called scabbing," observes Margaret Gullette, author of "Declining to Decline," which examines this phenomenon of pushing middle-aged workers off the plank. She laments the crushing impact on parents who lose jobs, their diminished ability to help their offspring with college and home-buying needs, and the way "the life course can be poisoned for each cohort as it turns 50 or even 40."

If the psychological blows are severe, so are many social impacts of privileging juniority. For instance, Columbia College in decades past would send 70 percent of its graduating seniors on to graduate school. Now, with lucrative job offers upon graduation, only 20 percent are going on for more schooling, which means fewer good professors and teachers in the next generation. Fields such as public service that do not yield vast wealth before 35 now seem devalued, careers for suckers.

Juniority has long been an American trait. We are a civilization that notoriously lacks "second acts." Is it just a coincidence that Al Gore had a dad named Albert Gore and W's dad is named George Bush? For years, Seattle's hero was a ballplayer simply called "Junior."

Media and advertising and retail also exert a powerful push toward youth culture. Advertisers gravitate toward young readers and viewers not because they have more money to spend but because their still-forming identities make them more susceptible to advertising's fantasy world. Generational solidarity - thinking in age groups, as by blaming boomers for keeping Xers from the good jobs - makes little social sense, but it does work for niche marketing and product differentiation.

No question, generational revolt is the fuel of Western individualism and progress. Oedipal urges intensify after a long period of high bourgeois complacency, as happened at the end of the long European peace of 1815-1914 and may be recurring after the long peace of 1945-2000.

The danger is when juniority becomes such a distorting force as to be a climactic disruption of the rhythms of life. If the effective work life ends at 45 (the bandwidth goes), then one better behave like a professional athlete (the knees go) and grab huge pots of money early. But when does the pursuit of the fountain of youth become a refusal to grow up?

Viagra notwithstanding, juniority is a losing game, a logical impossibility over time. "Tomorrow we die" produces an intensity for a while, but what happens when tomorrow you are still alive and unwanted?

A few years ago, I was visiting with a friend who had just survived a serious health scare. Approaching 50, he was still going out to clubs so he could hear loud music to late hours almost every night. "The doctor told me the three words I most dreaded hearing," he said as I girded myself for the worst.

Those terrifying words, which might have sounded rather comforting in a world less upside down, were: "Act your age." He was being stripped of his juniority. Please, Doc. Anything but that.

David Brewster's column appears alternate Fridays on editorial pages of The Times. His e-mail address is DavidBrew@AOL.com.