Hundreds of U.S. soldiers are set to deploy to the U.S.-Mexico border as a caravan of around 7,000 migrants moves north from Central America. 

Defense Secretary James Mattis could sign the deployment orders as soon as Thursday. The extra 800 or so troops would provide "logistical support" to the Border Patrol and the 2,100 National Guard troops already there.

President Trump reiterated his promise to send the military, calling the approaching caravan a "national emergency." The migrants, traveling on foot, are in southern Mexico, more than 1,000 miles away from the nearest entry point into the U.S.

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On "Outnumbered" Thursday, former GOP congressman Jason Chaffetz and Democratic strategist Adrienne Elrod debated whether a wall on the southern border is needed.

Chaffetz said Democrats have gone "far left" on immigration, supporting the abolishment of ICE, amnesty for illegal immigrants, sanctuary cities and "open borders." He said some even want to take down barriers that already exist on the Mexico border. 

Elrod said the wall is "not cost-effective" and would be "ineffective." She said Democrats support having more border agents, rather than construct a wall. 

Chaffetz said extra agents will make no difference if the law allows for migrants to be released into the U.S. He argued President Trump attempted to negotiate with Democrats on immigration, going "way out there" on a DACA fix and was rejected by Chuck Schumer and Nancy Pelosi. 

"To put this on Democrats is so irresponsible," Elrod answered, noting that Democrats do not control Congress or the White House. 

Kennedy said Democrats did have that control in 2008, but chose to pursue the "God-awful" ObamaCare bill instead of immigration reform. 

Watch the full debate above. 

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