Addiction skyrockets as drugs bound the US circulate within Mexico.
The spending bill Obama signed Wednesday eliminates a program that let some drivers deliver goods in the US.
At least 35 people were killed in 24 hours in the worst spate of bloodshed yet this year.
President Felipe Calderón's government has made a series of moves to clean up the country's police force. Results are open to interpretation.
Auto woes of the Big Three could hurt plants south of the border – and spur migration north.
Tijuana's anticorruption police chief was fired and replaced with an Army officer Monday, following three days of drug-related violence that left 37 people dead.