Because the Republicans delayed their convention so much that they ran right into the start of the Labor Day weekend, that end-of-the-summer holiday came and went with minimal attention paid to working Americans.

True, President Bush and John Kerry argued about the meaning of the latest unemployment report, which showed that the economy had added 144,000 jobs in August and that the unemployment rate had fallen to 5.4 percent. Bush said it spelled recovery; Kerry said it meant continued weakness.

But there is a larger story about workers and organized labor that has gone largely unnoticed this year. I was reminded of it by a conversation on the train coming back from New York. My seatmate, a fellow reporter, was asking questions about the changes I had seen in Congress since I started covering Capitol Hill almost 50 years ago. And when we got around to discussing lobbyists, he seemed genuinely surprised when I said that back then -- and for decades afterward -- the most influential lobbyists did not represent business or trade associations but labor unions.

"Labor unions!" he said, reflecting the understandable surprise of a savvy reporter who knows only the congressional power alignments of the past decade.

It made me realize how rarely observers like me make the link between the decline of progressive politics and with it the near-demise of liberal legislation, and the steady weakening of organized labor.

The economic effects of that trend are well documented. In the just-published update of their annual volume, "The State of Working America," Lawrence Mishel, Jared Bernstein and Sylvia Allegretto of the Economic Policy Institute chart the decline of union membership from roughly one-quarter of the workforce in the late 1970s to barely one-eighth today.

"This falling rate of unionization has lowered wages, not only because some workers no longer receive the higher union wage, but also because there is less pressure on non-union employers to raise wages," they write. And the gap is large. In 2003 the average blue-collar union job paid $30.76 an hour in wages and benefits, compared with $18.11 for the nonunion job.

A separate study, also released last week, by David Kamin and Isaac Shapiro of the Center on Budget and Policy Priorities, examined how the fruits of this current economic recovery have been allocated. In the 10 quarters since the recession officially ended in late 2001, 47 percent of the real national income growth has gone to corporate profits, and only 15 percent to wages and salaries.

Even if you add in the cost of health insurance and other benefits, as you should, the workers got only 43 percent -- well below the 61 percent average in eight previous recoveries. This is the first post-World War II recovery in which corporate profits grabbed a bigger share of the growth than workers' pay and benefits.

Both of these studies come from liberal think tanks, but the statistics are straight from the Labor and Commerce departments, and they suggest what the economic costs have been for the loss of labor's clout.

The loss of labor's political leverage is, if anything, even more striking. As I told my seatmate, when labor lobbied powerfully on Capitol Hill, it did not confine itself to bread-and-butter issues for its own members. It was at the forefront of battles for aid to education, civil rights, housing programs and a host of other social causes important to the whole community. And because it was muscular, it was heard and heeded.

Today, the shrunken Democratic caucuses in the House and Senate are probably closer to labor -- financially and politically -- than they were in the 1970s. But an enfeebled union movement is unable to sway more than a handful of Republicans. Richard Nixon, Jerry Ford and almost all of their GOP congressional leaders understood that it was in their interest to help labor achieve some of its goals. Now, unions cannot even muster the strength to force a vote on raising the minimum wage, which has not been changed in seven years.

Politicians took notice that even in the Democratic nomination contest, labor looked weak. Except for the firefighters union, which went with Kerry early, most of labor split its endorsements between Dick Gephardt and Howard Dean. Neither survived the Iowa caucuses, where labor is supposed to be a major force.

For those who think a Wal-Mart economy is the American future, the falloff in labor's influence is no cause for regret. But I suspect the country will continue to pay a price -- and not just union families -- until labor regains a place at the economic and political table.