People demonstrate in support of the Deferred Action for Childhood Arrivals program, known as DACA, in Los Angeles, in 2019.| Ted Soqui/SIPA USA, via AP At 7 years old, JeanCarlos Fiallos Manzanares crossed the U.S.-Mexico border illegally, hiding in the trunk of a taxi with his older sister. For more than a decade, he lived in the shadows in the United States. Salvation came, or appeared to, in his 20s, when President Barack Obama offered young immigrants like him protection from deportation.