And so ends another summer. No more swimmin' holes, hammocks, barbecues or lemonade. They're over, and summer's over.

That's what Labor Day is all about, right? The end of one season and the beginning of another? Wrong! Labor Day celebrates labor in the United States — the men and women who, through sweat of brow and dint of discipline, made this nation what it is, and who still do.

Labor Day has been around quite a while. The first relevant local ordinances passed in 1885; the first state law establishing Labor Day — Oregon's — passed two years later. Similar laws soon followed in 30 states, then a federal law in 1894. All this originated with Peter J. McGuire, general secretary of the Brotherhood of Carpenters and Joiners, who proposed a day to honor those “who from rude nature have delved and carved all the grandeur we behold.” On a good day, we still behold that grandeur, though too frequently we negate it thanks to outsourcing to places we'd rather not step foot in or because of a snotty, bourgeois reflex that elevates our minds above our hands.

In 1835, one of the first strikes in the United States occurred in the textile mills of Lowell, Mass. About 1,500 girls and young women — some under 10 years of age, most 16 to 25 years of age — walked out of the mills where they labored from 5 a.m. to 7 p.m., six days a week. They were furious that their bosses planned to slash their wages. Marching through the streets, the mill workers sang their favorite song, “I Won't Be a Nun”:

“Oh! isn't it a pity, such a pretty girl as I

Should be sent to the factory to pine away and die?

Oh! I cannot be a slave,

I will not be a slave,

For I'm so fond of liberty

That I cannot be a slave.”

The strike was a dud, and the bondage continued. The girls were back in the mills after a few weeks out of them, sweating through their 15-hour work days while silently humming “I Won't Be a Nun” — free of convents, but not of capitalists.

Around the same time, carpenters, masons and stonecutters in Boston demanded that their 13-hour work day be cut to 10. As in Lowell, these efforts also failed, and the men returned to work, no better off than before.

In the 180 years since these strikes in New England — the crude, not very successful origins of organized labor in this country — enormous strides have been made for the working stiff: Laws have shortened work hours and the work week, improved occupational safety, and guaranteed a minimum wage and some degree of family leave. Yet a certain huckster wants to erase most of that progress. In an interview on Fox News in July, Donald Trump took three contrary positions on the minimum wage in less than 30 seconds, first rejecting the need for a minimum wage, then promising he'd raise it “somewhat” (though not defining “somewhat”), and finally conceding that a minimum wage of $10 seemed reasonable, but “we'll let the states do it.”

Thus, Mr. Trump abandoned any presidential burden to ensure a humane living wage.

Mr. Trump has also told a gathering of women that they would receive the same pay as men “if you do as good a job.”

At least boys and girls working in 19th-century mills earned the same, even if was a pittance.

Mr. Trump has little regard for wages on his own projects: Trump Tower in New York was built on a site cleared by undocumented immigrant workers from Poland. When ruling on a lawsuit that had dragged on for 19 years, a federal court noted that the Poles were promised $4 to $5 an hour for 12-hour shifts, seven days a week. Instead, the court stated, they “were paid irregularly and incompletely, sometimes with personal checks, which were returned by the bank for insufficient funds.”

At least underpaid workers in 19th-century mills were underpaid on time.

And despite Mr. Trump's vaunted vows to return jobs to America, Trump regalia — shirts, eyeglasses, perfume, cuff links and suits — are made in Bangladesh, China, Honduras and other low-wage countries.

At least cotton was made in Lowell, even if those who made it could barely afford it.

So, no: Labor Day is not about the end of summer. It is about labor, which has come too far over too long a time to let an (alleged) billionaire turn back the clock so viciously, so unconscionably.

It's mind-boggling that Mr. Trump is so contrary to the American reflex for fairness and justice. If he gains the Oval Office, we risk not just defaming the worth of labor but unraveling the union that joins us as a people and as a nation, a union that derives its strength from labor, from the domain of law and community, and that flows from a well-crafted etiquette regarding camaraderie and decency. Labor Day exists to remind us, as the girls in the cotton mills of Lowell, Mass., sang, that we're

“… so fond of liberty

That I cannot be a slave.”

Summer may end today, but our yearning for liberty and dignity — the liberty and the dignity we forge with our hands and our hearts, our imaginations and our creativity — assuredly does not.

Arthur J. Magida's last book is “The Nazi Séance: The True Story of the Jewish Psychic in Hitler's Circle.” He is writer-in-residence at the University of Baltimore and can be reached at AMagida@ubalt.edu.