7 Min Read LOS ANGELES (Reuters) - U.S. President Joe Biden has moved swiftly to start dismantling a cornerstone of former President Donald Trump’s hardline immigration policy, a program that sent thousands of asylum seekers back to Mexico to await their immigration court hearings. FILE PHOTO: Migrants hold a protest at the Mexico-U.S. San Ysidro port of entry to ask U.S. President Joe Biden to allow them to apply for asylum, in Tijuana, Mexico March 2, 2021. Picture taken March 2, 2021. REUTERS/Jorge Duenes/ Biden’s focus on ending the Migrant Protection Protocols (MPP) - under which 65,000 migrants were sent back to Mexico - fulfills a key election campaign promise, but it leaves thousands of migrants not in the program unsure of their fate, migrants, attorneys and activists told Reuters.