Some recent correspondence I had with a colleague about Chinese immigration to the U.S. in the 19th century prompted this post. There has been some great historical work on the Chinese immigrants in the last few decades, but it's difficult to overcome the myths propagated for decades by labor unions and their academic apologists. My article Lochner, Parity, and the Chinese Laundry Cases, can be found here.
Myth: The Chinese were "coolies," which means that they were hired out to an employer for a certain number of years in exchange for their passage to America, and could not leave until their term of service was over. Coolies were often treated worse than slaves, because they had no "residual value" to their employers once their term of service was over.
Fact: While many Chinese arrived in South America as coolies, in the U.S. they did not. Rather, they borrowed money to pay for their voyage, and then worked as free laborers in the U.S., using their earnings to pay back the cost of their journey.
Myth: Corporate barons "imported" Chinese workers to take jobs that would otherwise be held by American workers.
Fact: Like whites, most Chinese came to the West to participate in the Gold Rush. They were eventually forced out of the gold mines by legislation and violence. Many of them then found work on the Transcontinental railroad.
Myth: The Chinese were taking "American" jobs, leading to hostility against them.
Fact: First, the most vociferously anti-Chinese workers tended to be immigrants themselves, especially, though not exclusively, from Ireland. To take one interesting example, Henry Weissman, an immigrant from Germany who later became head of the N.Y. bakers' union and even later became and attorney and won the Lochner case for the bakers, was involved in anti-Chinese activity almost as soon as he arrived in California.
Even more significant by 1882 (the year of the first Chinese Exclusion Act), the Chinese had been driven out, often with violence, sometimes with legislation, from most industries, and overwhelmingly made their living in fields where they didn't directly compete with white workers--agriculture, laundries (absolutely dominated by the Chinese), and domestic service.
So, beyond the concern that the Chinese might compete with them in the future, why did labor unions continue to so vociferously oppose the Chinese?* In part, because it appealed to their racist constituents, but more so because it made them look "public-spirited" and not just self-interested, the latter an obvious barrier to labor union popularity; they were seen as standing up for whites against the "yellow hordes," even when it didn't directly benefit them. It's funny to see Chinese exclusion as the 19th century equivalent of, say, participating in an "adopt a highway" program, but there you have it.
*Trivia note: the "union label" was a white label invented by the California cigarmakers' union to allow consumers to easily distinguish union-made cigars from Chinese-made cigars. The cigar boxes were stamped "WHITE LABOR."