On the main road into El Cargadero, most homes are locked up and gathering dust. On a recent afternoon, there were only two people on the street: an old man in a wheelchair and another with a cane. The sound of a radio inside a home blocks away could be heard as clearly as the men’s conversation.

Nearly everyone in the town has relatives in the United States — one woman counted 150 — but the families still here tend to be intact, suggesting that legalization would be less of a magnet than before. And there are simply not as many young people over all: the birthrate across Mexico has fallen from nearly seven children per family in 1970 to just over two, partly because of a government push for family planning. Mr. Saldivar, the avocado farmer, says his daughter’s sixth-grade class has seven students, compared with 30 when he attended.

He doubted that his three children would bother heading to the United States. His son is in a college preparatory program. He and his wife, whose nine siblings are also all in the United States or Canada, live comfortably in a small, well-kept home with flowered curtains. Their main nod to migration is linguistic: they pay an English teacher to instruct their children so they can communicate with their American cousins. They are among the many here who no longer see the United States as a dreamland, recoiling at the anti-immigrant sentiment there and the stories of struggle that relatives share in phone calls and e-mails.

At least initially, many Zacatecans said, legalization may actually send more people south than north, as millions of immigrants would be able to come and go from the United States legally for the first time in years.

J. Reyes Sanchez, 53, one of the men chatting near the church, said he wanted nothing more than to see his three children in the United States, and his American grandchildren, and a pathway to citizenship could let that happen. “They could come see their family, they could come see me,” he said. “They’d practically be tourists here, but they need to come.”