Last year the Border Patrol arrested and deported 229,178 Mexicans and 257,473 Central Americans. Mexicans represented less than 47% of the total number of arrests for the first time.
Sponsored by Rubén Gallego, Democratic representative from Arizona, the proposal would open the possibility of military service to about 600,000 "Dreamers".
More than 200 people were injured in the wreck that plunged screaming passengers into darkness and chaos Tuesday night.