(CNN) - Republican presidential hopeful Herman Cain maintained Monday that his remarks about building a lethal electrified fence on the U.S.-Mexico border were a joke, but he said he probably should have been more sensitive when choosing his words.
"Yeah, it was a joke, and yeah, I haven't learned how to be politically correct yet," Cain said on CNN's "John King, USA."
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"So yes, it was probably not the correct thing to say, and I didn't mean to offend anybody."
When asked what he would tell Latinos who might be offended by his remarks, Cain emphasized his plan to help immigrants gain legal citizenship.
"What I would say to them is, I'm all about making it easy for people to come to this country," Cain said. "We have wide-open doors. I have talked repeatedly about wanting to make it easy for people to come to this country the legal way - cleaning up the bureaucracy in Washington, D.C. Those kinds of things never get reported on. But I am all for opening up the doors of this nation."
Cain said a border fence was only one element of his immigration plan.
"I think we need a combination of a physical fence in some instances - we can use technology for some parts - and some of the more dangerous parts, what we need to do is put boots on the ground in order to secure the border," Cain said. "I am tired, like the American people are, of hearing about citizens being killed, citizens being threatened, and some border agents' lives being threatened."
Cain wouldn't respond to a recent analysis that predicts higher taxes for Americans under the candidate's "9-9-9" tax plan.
"I am not going to comment on those calculations, because I don't know what assumptions they used," Cain said. "Here is a fact: It would depend upon what that family spends their money on."
Cain was responding to an analysis by the non-partisan Politifact, which determined that for tax payers who are married with dependents, the 9-9-9 plan would result in higher taxes.
Cain said that under his own calculation, people who buy mostly new goods would end up paying more under his plan, since the 9% sales tax that is included doesn't apply to used goods.
"The people that would pay more are the people who would buy mostly new goods," Cain said. "That's how it will be determined. So since I don't know what people's buying habits will be, it's hard to say who will pay more."
Ultimately, Cain maintained that most people would see a tax reduction.
"Most people won't be paying any more in taxes than they are paying today, probably a lot less," Cain said.
On another issue, Cain told CNN that he would authorize U.S. commanders in Afghanistan to launch a drone strike or fire back into neighboring Pakistan if they had proof that attacks on U.S. soldiers were coming from across the border.
"I wouldn't hesitate to give them the authority to defend themselves and to fight back," Cain said.
–CNN's Tom Cohen contributed to this report.