Long stretches of the border are under the supervision of nearby military bases, empowering U.S. troops to detain people entering the country illegally.
Lance Cpls. Albert Aguilera and Marcelino Gamino died in a vehicle crash while supporting border operations. A third Marine remains in critical condition.
The move could allow the Trump administration to get around a federal law prohibiting U.S. troops from being used in domestic law enforcement on U.S. soil.
By Tara Copp, AP and Lolita C. Baldor, The Associated Press