On the heels of yet another North Korean missile test, albeit one the Pentagon says failed, and ahead of a meeting between President Donald Trump and his Chinese counterpart, Trump’s first choice for Secretary of Defense told Fox News the U.S. is right to consider first-strike military action against Pyongyang.

“We’re rapidly and dangerously heading towards the reality that the military option is the only one left when it comes to getting North Korea to denuclearize and not weaponized [intercontinental ballistic missiles]," said retired four-star Gen. Jack Keane.

Keane said going to war is undesirable to the Trump administration because of the toll it would take on human lives.

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“But the Trump administration cannot accept a nuclear launch,” he said. “We cannot rely on our missile-defense system to defeat it and expose the American people to a nuclear attack. Therefore if an ICBM attack was imminent the president would have to conduct a preemptive strike.”

Such a position is intended to send a message to Chinese leaders ahead of tomorrow’s meeting at Trump’s Mar-a-Lago residence in Florida.

“Three past presidents have sought political, economic and diplomatic steps to get North Korea to denuclearize but failed miserably,” Keane said. “All three tried to leverage China but also failed.”

Keane said that while former President Obama never fully removed the military option – a move Obama called “strategic patience” – both China and North Korea believed he had done so.

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The Trump administration has said that policy is not working and plan to put the military option back on the table, Keane said.

“North Korea ought to be at the top of the agenda in Mar-a-Lago,” said John Bolton, former U.S. ambassador to the United Nations. “How much do you fear a nuclear weapon? That's the question. We have to look at preemptive military action. If China doesn't like that prospect maybe we can start bringing down the regime with other measures, like cutting off the supply of food and fuel to North Korea.”

The Trump administration is said to be considering a range of new sanctions against the North Korean regime. But, as in the past, such moves require help from Beijing. That help has not often been forthcoming.

“The U.S. has tried to get the Chinese to cut off oil and food to the North Koreans for 23 years, only to be told that Beijing does not believe in cut-offs of anything,” said J.J. Tkacik of the International Strategy and Assessment Center. “The Chinese have acquiesced in several UN Security Council resolutions that involve some level of trade and economic sanctions, but there has never been any indication that they actually have implemented those sanctions.”

There is broad agreement that what North Korea is doing is dangerous and unprecedented. In his first five years as North Korean leader, the Center for Strategic and International Studies points out that Kim Jong-Un has ordered more than twice the number of missile tests than his father, Kim Jong-Il, did during his 17-year rule.

“It has invested heavily in the development of increasingly longer range ballistic missiles, and the miniaturization of its nascent nuclear weapons stockpile,” according to a report by the non-partisan CSIS. “North Korea is reliant on these capabilities to hold U.S., allied forces and civilian areas at risk.”

Keane said what is particularly dangerous is Kim Jong-Un’s rhetoric that he intends to use these weapons against the United States.

“There’s not another world leader who says he intends to use nukes against the U.S.,” Keane said. “We have to take this threat very seriously.”

In his meeting with Chinese President Xi Jinping, Trump could try to get help from China. But experts say even if that does come up, China would likely not agree to it.

“North Korea has strategic value to China,” said Shen Dingli, vice dean of international relations at Fudan University in Shanghai, and a frequent commentator on U.S.-China relations. “The U.S. has to end its military threat to China, on the issue of Taiwan, before asking China to do it a favor by demanding something from North Korea.”

But experts said Trump’s candor and blunt approach is appreciated in China and could help him.

“Being unpredictable and questioning conventional wisdom can be an effective strategy at times,” said Paul Haenle, who served on the national security staffs of Presidents Bush and Obama. “A healthy dose of unpredictability is useful in our strategy with China.”

Still, some experts said Trump has to be careful in how he deals with China and North Korea. Any provocation, they say, could backfire.

“If the U.S. attacks without provocation, China is legally bound to defend North Korea,” said Shen Dingli, vice dean of international relations at Fudan University in Shanghai, and a frequent commentator on U.S.-China relations. “Don’t expect China to let North Korea collapse. China will join North Korea to a level that will prevent its collapse.”

Keane said President Trump is going to be diplomatic, but he isn’t afraid to urge China to take sides.

“[Thursday], we’re going to try the diplomatic option to reverse North Korea’s nuclear program,” Keane said. “As for the military option, we’re moving there because Beijing, you’ve painted us into a corner. Let’s work together and denuclearize North Korea. I don’t know if they’re going to do that. But we’ll see.”