Jane Garcia, CEO of La Clinica de la Raza, which serves 25,000 patients in Contra Costa County, Calif., addresses supporters of expanding health care for undocumented adults. Farida Jhabvala Romero/KQED hide caption

itoggle caption Farida Jhabvala Romero/KQED

Donald Trump speaks to the media at the U.S.-Mexico border in July. The Libre Initiative's letter doesn't call out any candidates by name, but Trump has called for mass deportation and an end to birthright citizenship for immigrants. LM Otero/AP hide caption

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Mexican and Mexican-American families wait to board Mexico-bound trains in Los Angeles on March 8, 1932. County officials arranged these mass departures as part of "repatriation campaigns," fueled by fears that Mexicans and Mexican-Americans were taking scarce jobs and government assistance during the Great Depression. Los Angeles Public Library/Herald Examiner Collection hide caption

itoggle caption Los Angeles Public Library/Herald Examiner Collection

Butler County Sheriff Richard Jones stands next to a illegal aliens sign he had placed in the parking lot of the Butler County Sheriff's Department, Nov. 3, 2005, in Hamilton, Ohio. David Kohl/AP hide caption

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Republican presidential candidate Donald Trump speaks at a press conference Wednesday prior to a town hall meeting at Pinkerton Academy in Derry, N.H. Matthew Healey/UPI/Landov hide caption

itoggle caption Matthew Healey/UPI/Landov

Donald Trump wears what's become a campaign signature: his "Make America Great Again" hat. Part of making the country great again, Trump says, is implementing his hard-line immigration plan. Scott Heppell/AP hide caption

itoggle caption Scott Heppell/AP

Donald Trump continues to lead in the polls and on Sunday released his first policy position — a conservative proposal on immigration. Seth Wenig/AP hide caption

itoggle caption Seth Wenig/AP

Detainees at the Northwest Detention Center in Tacoma, Wash., gather for a Sikh prayer service. Liz Jones/KUOW hide caption

itoggle caption Liz Jones/KUOW

Tunde Wey gets ready to serve plantains and Jollof rice at his pop-up Nigerian dinner in the kitchen of Toki Underground, a ramen restaurant in Washington, D.C., in December 2014. Eliza Barclay/NPR hide caption

itoggle caption Eliza Barclay/NPR

Marta Elsie Leveron, 19, (left) and her brother Freddy David Leveron, 18, have not seen their father since he left El Savador to work in California in 1999. A new U.S. program allows families to reunite if one parent is a legal U.S. resident. The girl in the middle is Liliana Beatriz Leveron, 16, a cousin of the other two. Her parents are in the U.S. and she's seeking to reunite with them as well. Carrie Kahn/NPR hide caption

itoggle caption Carrie Kahn/NPR