Their deployment, which begins Aug. 1, is expected to last at least a year.
Drug-violence has recently exploded in Mexico, and that violence has been spilling into the U.S. In California, 224 troops will be on patrol. As for the rules of engagement?
"The National Guard will be there to support the efforts of law enforcement," said Commissioner Alan Bersin with U.S. Customs and Border Protection, "not to confront unless confronted by any particular threat."
The beefed-up plan comes as the debate over illegal immigration intensifies in the U.S. Critics say the federal government has not done enough to tackle the problem.
Federal officials say the border is more secure then ever.