A U.S. Border Patrol agent guards a group of Mexican immigrants caught after they crossed into the United States on March 6, 2013 near Walker Canyon, Arizona.
If Congress passes immigration reform, it's likely to include tens of billions of dollars for border enforcement. But the last time the government tried to go big with border security, it encountered some pitfalls. Federal officials are trying to learn from past mistakes as they shop for technology to secure a key stretch of the border. Reporter: Jude Joffe-Block