>> We're going to stop people from coming into our country illegally.>> With an eye on overhauling US policy on immigration, President-elect Donald Trump choosing retired Marine General John Kelly to lead the Department of Homeland Security. Kelly commanded US troops in Latin and South America, making him well briefed on the flow of immigrants.
Foreign policy correspondent Warren Strobel.>> So by all accounts, General John Kelly is a Marine's Marine. He enlisted in 1970 in the Marines and spent 45 years as a Marine in the US military. During some Senate testimony a couple of years ago, he warned quite starkly about the dangers posed by the poorest US Southern boarder with Mexico.
And that stance puts him in the same place as President-elect Trump, who has promised to build a wall and make Mexico pay for it.>> Kelly becoming the third former general to be tapped by Trump. Along with retired Marine General Mad Dog Mattis chosen for Defense. And retired Lieutenant General Michael Flynn, who will be Trump's National Security Advisor.
>> It's interesting that Trump said during the campaign that I know more than the generals. I know more than they do about ISIS. He seemed to be putting down the US military. But as he goes through this transition process, he's in fact choosing over and over to go with retired military men, when there are other candidates out there.
So I think that tells us something about Trump. He seems to bond with these individuals. He seems to like the military culture and probably the plain spokenness of the military.>> Mattis out of service for only three years, not the seven years required to be Defense Secretary. He'll need a special waiver from Congress.
Senate Republicans already working to attach the waiver to a budget bill to clear the way.