The guestworker program continued but in recent years abuses have gotten nastier. When growers demanded a bigger and less regulated program in 1986, the Labor Department waived Wirtz-era rules restricting the program. Now agricultural guestworkers work all over the United States and come from as far away as Peru and Thailand, though most are Mexicans.

Growers have turned to for-profit recruiting agencies to handle the paperwork, which has led to some of the ugliest human trafficking cases in post-emancipation U.S. history: workers never paid, fraudulently charged thousands of dollars for low-wage, temporary jobs, housed in storage sheds or in flooded post-Katrina hotels.

Most shocking of all: The regulatory system that agricultural employers complain so bitterly about did not function at all (until the current administration). Despite gross violations of H-2A rules in the 1990s, for example, the Labor Department cited only one company (for failing to pay minimum and overtime wages), and did not deny that company’s requests for more guestworkers. Indeed, the GAO reported in 1997 that “the Department of Labor had never failed to approve an application to import H-2A workers because an employer had violated the legal rights of workers.”

Today, any notion of doing without immigrant workers in agriculture is probably fanciful, but under what terms? Until guestworkers have the right to change employers, complain without fear of deportation, bargain collectively, make use of Legal Services, sue in federal courts, and some day settle down like other immigrants, we had better keep and enforce the bad old rules. They were put there for a reason.

Cindy Hahamovitch is the Class of ’38 Professor of History at William & Mary and the author of “No Man’s Land: Jamaican Guestworkers in America and the Global History of Deportable Labor.”