Sen. John McCain (R-AZ) says there is no proof that gun control leads to less gun violence, but he is willing to "look at everything" following a massacre in Aurora, Colorado that left least 12 dead and 58 wounded.

"I don't know, to tell you the truth, what we can do, and this immediately leads to the issue of gun control," McCain told CNN's Candy Crowley. "The killer in Norway, which is a country that has very strict gun control laws, and yet he was still able to acquire the necessary means to initiate and carry out a mass slaughter."

"I think we need to look at everything, if that even should be looked at, but to think that somehow gun control is -- or increased gun control -- is the answer, in my view, that would have to be proved," he added.

Crowley noted that James Holmes, the suspected Colorado shooter, had, over short period of time, purchased an arsenal of weapons and equipment, including an AR-15 semi-automatic assault rifle with a 100-round magazine, two Glock handguns, a Remington 12-gauge shotgun and various types of body armor.

"You get to this point, you don't want the government spying on what people are buying," she explained. "On the other hand, what's the price? The price is all these things we just read off."

"Let's remember it's a constitutional right," McCain replied. "Second of all, if you could prove the case that it, indeed, has a positive effect -- we had a ban on assault weapons that expired some years ago, it didn't change the situation at all in my view."

"So, I think the strongest Second Amendment rights people would be glad to have an conversation, but the conclusion that this was somehow caused by the fact that we don't have more gun control legislation, I don't think has been proved."

According to a 1997 study (PDF) published in the International Journal of Epidemiology, the U.S. had a firearm homicide rate 23 times higher than Norway, which McCain cited in his remarks.

More recent 2009 data showed that the U.S. had a firearm homicide rate that was about 15 times higher than "populous, high-income countries," and 10 times higher than the "western countries" belonging to NATO.

Watch this video from the CNN's State of the Union, broadcast July 22, 2012.

(h/t: Talking Points Memo)