As America observes the century's last Labor Day, workers are reaping the benefits of the best economy in modern history. But whether the nation's work force continues to prosper and post gains in income and financial security will depend largely on some critical decisions that Congress and the president will make in the coming months.

We're in an economic expansion that just won't quit. At 4.3 percent, our unemployment rate is the lowest since 1970, and the lowest of any major country. More than 64 percent of the adult population is working today -- more than ever before in our history. Inflation remains at an insignificant level. Real wages have increased nearly 5 percent in just the past two years. Home ownership is at an all-time high.

Since 1990, household financial assets have doubled, and since 1995, the increase in household financial assets for each year was equivalent to nearly one-half of disposable after-tax income for all households. Millions of Americans own stock directly, and millions more own stock indirectly through pension funds. That's a clear sign that Main Street and Wall Street are becoming one and the same.

While politicians are quick to take credit for the booming economy, most of the credit belongs to American companies and their employees -- especially the millions of small businesses and self-employed entrepreneurs who take most of the risk, spur most of the innovations and create most of the new jobs in our country.

Yet while government may not have created the current expansion, it will have a profound impact on whether prosperity continues and whether on Labor Day in the year 2000 working families are still moving forward or are in a period of decline.

How the nation's policymakers answer four critical questions in the coming months will, in large part, define workers' economic prospects as we enter the new millennium:

Will Uncle Sam give workers a raise in the form of a tax cut -- a tax cut that also would boost investment and productivity and thus fortify economic expansion?

Will the government threaten health care coverage for the 150 million Americans who get insurance through the workplace by enacting so-called managed care reforms, such as new mandates and patient lawsuits?

Will the United States embrace free trade policies that enable American businesses to create millions of higher-paying export-related jobs for our workers -- or will we surrender those exports and jobs to other countries?

Will the "Fourth Branch" of the federal government -- that is, the regulatory agencies -- be permitted to impose costly and burdensome new rules in areas such as ergonomics and the environment? Ironically and unfortunately, the leaders of organized labor -- who now represent just more than 9 percent of the private-sector work force -- continue to take positions on these critical issues that would harm the small minority of workers they represent and the vast majority they don't.

Claiming Labor Day as their own, the unions no doubt will use the occasion to articulate the case for an expanded government role in the economy and greater regulatory control over business.

Perhaps some day, union leaders and those in Congress who subscribe to their anachronistic agenda will explain how high taxes, scarcer and costlier health coverage, fewer U.S. exports and an oppressive new layer of incomprehensible regulation help American workers and their families.

Business isn't holding its breath. But on this Labor Day, we join in honoring the best and most productive workers in the world. And, we will thank them in part by continuing to fight for the kind of high-growth, low-tax policies that represent a true workers' agenda for the 21st century.

The writer is president and CEO of the U.S. Chamber of Commerce.