Rep. Beto O’Rourke, D-Texas, a possible challenger to Sen.Ted Cruz, R, in 2018, argues that a fluid border between El Paso and Juarez, Mexico, has been good for both cities. : Photo by Ivan Pierre Aguirre for The Washington Post – For The Washington Post Rep. O’Rourke speaks to a constituent in the middle of the bridge between El Paso and Juarez.