McCain, R-Ariz. the chairman of the Senate Armed Services Committee, added that China will be "key" in how the world addresses the situation.
"They can stop this if they want to because of their control over the North Korean economy," McCain said on "Meet the Press."
"There are artillery on the border between North and South Korea that can reach Seoul and we can't take them all out before — I mean, this is a very serious. This may be the first test of this presidency. But China can shut them down. Whether they are currency manipulators or not, we should expect them to act to prevent what could be a cataclysmic event."
Early Sunday morning local time, North Korea attempted to launch a missile, but U.S military officials told NBC News that it failed "almost immediately."
In a statement Saturday, U.S. Defense Secretary James Mattis said, "the president and his military team are aware of North Korea's most recent unsuccessful missile launch. The president has no further comment."
Tensions with the country are "very serious," McCain said. "This guy [leader Kim Jong Un] in North Korea is not rational. His father and his grandfather were much more rational than he is."
Also on "Meet The Press," the Ranking Member of the Senate Armed Services Committee, Sen. Jack Reed, D-R.I., affirmed that he wants to see "a very deliberate plan" on North Korea from the administration.
"I think you have to have a strategy," he said, adding that President Donald Trump is "getting good military advice from General Mattis and Lt. Gen. McMaster but he needs a much stronger State Department."
McCain also said he wanted to see the administration present a strategy for Syria and other areas where the U.S. is engaged.
After Trump ordered strikes of a Syrian airfield earlier this month following a deadly chemical weapons attack that the U.S. believes was committed by President Bashar Assad's regime, McCain supported the action and said he believed the president is "growing." But, McCain said, the overall strategy is "not apparent."
"We've got to develop a strategy. There is still not an overall strategy that he can come to Congress and his advisers and say, 'okay, this is how we are going to handle Syria. Here's how we are going to handle post-Mosul Iraq,'" McCain said. "We've got to have a strategy and I'll give them some more time but so far that strategy is not apparent."
In the last two weeks, the Trump administration has offered mixed messages on the United States' long-term goals in Syria and whether the White House felt Assad must go. McCain argued that the administration should go further.
"Of those 400,000 men, women and children who were slaughtered [in the Syrian war], they weren't slaughtered by ISIS. They were slaughtered by Bashar Assad," he said.
"The war crimes are horrendous here and to just say, 'We're only after ISIS,' in my view, rather than regime change, is something that we have to re-think," McCain added.
Reed, meanwhile, believes that the pursuit of ISIS in Syria is legally covered by the current AUMF (Authorization for the Use of Military Force), and he supported the strike on the Syrian airfield. But, he felt, "anything further" should be considered by Congress.
"Going after Assad in terms of the deliberate concentrated effort to conduct military operations would require the authorization of Congress," Reed said.