Chris Christie just launched a broadside against Jeb Bush

New Jersey Gov. Chris Christie (R) is taking aim at former Florida Gov. Jeb Bush (R) over foreign policy and taxes.

In an interview on Tuesday with Laura Ingraham, Christie criticized Bush for trying to "re-litigate" the Iraq war, a day after Bush laid out a broad foreign-policy vision during a major speech at the Ronald Reagan Presidential Library.

"There's no reason to go back and try to re-litigate this. It's bad decision-making by Gov. Bush, but I'm not running his campaign," Christie said. "It makes no sense for us as a party. We know what the answer to that is."

"Common sense will tell you that this is not a fight that we want to have again," Christie added.

Earlier this year, Bush stumbled in his response to questions about whether he supported his brother and former President George W. Bush's decision to invade Iraq. Though the former Florida governor now admits that "mistakes were made" in Iraq, he hasn't shied away from talking about the issue.

Christie also went after Bush over his refusal to sign prominent conservative Grover Norquist's famous pledge not to raise taxes, which almost every other Republican presidential candidate has signed. Americans for Tax Reform, the group Norquist heads, announced Wednesday that Christie had signed the pledge.

"I wonder why Gov. Bush won't sign the pledge," Christie said. "It doesn't make any sense. If your record is consistent with that, and your philosophy is consistent with that, which mine is, I saw no problem with that."

Christie also claimed that his decision to sign the pledge was much more politically precarious than when Bush was governor of Florida.

"It's what I've done in New Jersey under much more difficult circumstances than Gov. Bush faced in Florida with a Republican legislature," Christie said.

Norquist recently said he isn't exactly sure why Bush hasn't signed the pledge, but he praised Bush's record on taxes as governor.

"I think he's just being ornery. He didn't sign as governor. Now, he never raised taxes, and he was very good about that," Norquist told Business Insider in an interview last month.

Norquist also suggested that Bush was refusing to sign it because his father broke the pledge and raised taxes, infuriating Republicans in an episode to which many political observers attribute his 1992 election loss.

"Putting on my Oedipal, Psych 101 thing - dad did it. Dad tripped. Taking the pledge is dissing dad. Dad's very sensitive to this," Norquist said.

Christie's attacks on Bush likely won't be the last barbs traded between the two.

Bush, Christie, and Ohio Gov. John Kasich (R) are all investing significant resources in New Hampshire, the first-in-the-nation primary state, which is seen as crucial to carrying forward momentum. New Hampshire is book-ended by contests in Iowa and South Carolina - two states that typically go to more conservative candidates - and few candidates recover after low finishes in the first three states.