For 17 1/2 years, Morley Cohen thrived in his full-time job as a liquor salesman, enjoying his San Fernando Valley route and living comfortably on an annual income of about $45,000.
But late last year, it all fell part. Cohen's employer shut down, and he was forced to scramble to come up with part-time sales work. His income shriveled, and he lost his company-paid health care benefits.
"It's a shocker after that many years to leave with nothing," said Cohen, 63. "Any way I can make a dollar, I'll make a dollar."
In an era of heightened job insecurity, the image of such a fall from a well-paying, full-time position to a marginal part-time job haunts many workers. And the fact that adding part-time jobs often threatens the wages, benefits and economic security of full-time workers has spurred many unions to fight companies moving in that direction.
In fact, one of the key triggers that sparked the nationwide strike launched by the Teamsters Union last week against 22 trucking companies was the employers' proposal to start using lower-paid, part-time dock workers.
In some industries, labor leaders regard part-timers as union busters. In a strike, part-timers can sometimes step into the jobs of those on the picket line. Full-timers "fear that they're training their own replacements," said Dale Belman, a labor economist at the Economic Policy Institute.
Even apart from strikes, Belman added, the lower wages and benefits often paid to part-timers provide "a very strong dynamic for firms to reduce the number of full-time workers and replace them with part-timers."
Part-timers are hard to organize, and, especially if they hope to move up to full-time positions, they are likely to be far more reluctant to challenge management.
Yet the vision of legions of employers demoting workers from full time to part time, or laying off full-time workers to make room for lower-paid part-timers, masks a more complicated pattern in the U.S. economy.
To be sure, part-timers generally receive substantially fewer benefits and often lower hourly pay than their full-time counterparts. In addition, the number of "involuntary" part-timers--people who hold part-time jobs because they can't find full-time work--has climbed over the years, although they still account for less than a third of all part-time workers.
Moreover, there has been a boom in a related type of worker--temporary employees--who also have less than a full-time stake in the companies employing them.
But over the last two decades, Labor Department figures show there has been no surge of part-timers pushing full-time workers out of their jobs. The number of part-timers shot up over that period, but the ranks of people working 35 hours or more a week rose almost as quickly.
From 1973 to 1993, the percentage of working people holding part-time jobs rose only slightly, from 16.6% to 18.8%, with involuntary part-timers accounting for the increase.
The key issue, according to Georgetown University labor economist Stanley D. Nollen, is not that part-timers are replacing full-time workers but that "part-time people aren't being treated equitably."
While government statistics show that part-timers earn much less than full-timers, part of the reason is that part-time jobs are more prevalent in low-paying industries such as restaurants and retailing. Still, even when efforts are made to compare part-time and full-time workers in similar jobs, a big gap remains.
For instance, according to the Washington-based Economic Policy Institute, women working part-time in administrative support and clerical jobs earn 16.5% less per hour than their full-time counterparts. And 25.6% of women who work part time and head households receive health care benefits, compared to 74% of similar women working full time.
Not everyone, of course, sees working part time as a hardship. Part-time jobs can be a boon to students putting themselves through college, parents trying to balance the demands of work and family, and moonlighters looking for extra income.
Periodically over the years, employers and unions have clashed over proposals to add part-time workers. Supermarket and transportation businesses have led the way, largely because they have distinct busy and slack work periods.
"In any industry you pick where there isn't a level work flow, you're going to get those pressures from management," said Daniel J.B. Mitchell, a UCLA labor economist.
But Mitchell noted that one factor that could reverse the trend is health care reform. He explained that if employers are required to provide health insurance for all workers, full and part time, that could provide more of an economic incentive to rely more on full-timers.
At the same time, part-time jobs can be a boon to companies and their employees, enabling firms to stay in business by holding down labor costs and using their work force more efficiently.