(CNN) Scott Walker says he would rip up the Iran nuclear deal on Day 1 of his presidency, even if it means the U.S. would have to go it alone -- without key allies.

"I think it's that bad of a deal, it's a bad deal for us, it's a bad deal for Israel, it's a bad deal for the region," Walker told CNN during an interview aboard a campaign Winnebago driving through Iowa. "It's not just the starting gun, it will accelerate the nuclear arms race, and it is empowering Iran to do what they're going to do."

"Lifting the sanctions (and) giving them credibility in the world not only emboldens the problems we have in terms of their illicit nuclear infrastructure, but this is the leading state sponsor of terrorism this is a direct threat to Israel," Walker said.

Jeb Bush tweaked Walker last week, not so subtly suggesting the Wisconsin governor is naïve, by saying he would not throw out the Iran deal on his first day in office because the responsible thing is to first form a cabinet, and talk to U.S. allies.

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