Moderator Chuck Todd asked Walker whether he would support building a wall along the long northern border.
"Some people have asked us about that in New Hampshire," Walker responded. "They raised some very legitimate concerns, including some law enforcement folks that brought that up to me at one of our town hall meetings about a week and a half ago. So that's a legitimate issue for us to look at."
Walker added that securing the borders means not just building a wall but also ensuring that the "intelligence community has the ability for counterterrorism and the ability to go after the infrastructure they need to protect us."
Although immigration has long been a key issue for Republicans as they pick their presidential nominee, Donald Trump — the bombastic businessman and television celebrity who is now the GOP front-runner — has blown up that discussion by pushing a controversial and pricey proposal under which all illegal immigrants would be deported, a massive wall would be constructed along the southern border and U.S.-born children of illegal immigrants would stop getting automatic U.S. citizenship. It has been difficult for other candidates to distinguish themselves on this issue, although several are trying.
New Jersey Gov. Chris Christie (R) said during a campaign event in New Hampshire on Saturday that the United States should track foreign visitors just like FedEx tracks packages — and that, as president, he would ask Fred Smith, the founder of FedEx, to work for the government for three months to set up such a system.
In an interview with ABC's "This Week" that aired Sunday, Louisiana Gov. Bobby Jindal (R) said immigrants who come to the country legally should immediately "learn English, adopt our values, roll up our sleeves and get to work." Jindal is the son of immigrants from India and has called for an end to "hyphenated Americans."