Sen. John McCain Thursday called for U.S. military action in Syria to end the carnage that has claimed more than 400,000 lives and displaced millions.

In an op-ed piece in the Wall Street Journal, McCain called the Obama administration policy on Syria a miserable failure and called for a “new strategy — including the necessary military component.”

McCain said the first step is to ground President Bashar Assad’s air force and making clear to Russia its aircraft will be at “greater risk” if its “indiscriminate bombing” doesn’t end. He said Congress is ready to support a military option as long as a broad strategy is articulated.

McCain said it’s no surprise the latest cease-fire collapsed in light of the administration’s approach, quoting former Secretary of State George Schultz, who once said, “Diplomacy not backed by strength will always be ineffectual at best, dangerous at worst.”

The Arizona Republican called Secretary of State John Kerry’s decision to suspend talks with Russia “meaningless.” Assad blamed the collapse on U.S. unwillingness to work with Russia to fight extremists.

“Meanwhile, Mr. Assad and Mr. Putin are creating military facts on the ground in Syria that will enable them to dictate the terms of a peace secured by carnage,” McCain said. “They have decimated coalition-backed Syrian groups, slaughtered countless civilians, consolidated the Syrian regime’s hold on power, and even struck a United Nations humanitarian-aid convoy. And they have done all of this with no consequences. Thus the war grinds on.”

McCain conceded the U.S.-led coalition is making progress against the Islamic State group, but said the terrorist organization is just a symptom of the overall civil war and predicted the conflict will worsen unless the U.S. takes action.

“It will produce millions more refugees, undermining regional stability and straining the social fabric of Western nations. It will strengthen an anti-American alliance of Russia and Iran,” McCain said. “U.S. credibility with our closest security partners in the Middle East will further erode. And it will provide ISIS, or its successor groups, fertile ground to radicalize Muslims, recruit and inspire them to fight, and provide them with dangerous battlefield experience.

“This is where the conflict in Syria is headed, and the administration still has no strategy to do anything about it. Its diplomacy is toothless. And there appears to be no Plan B.”

The Syrian army Wednesday promised to reduce air strikes on eastern Aleppo on humanitarian grounds now that it has succeeded in cutting off all entry roads used by insurgents, Reuters reported. Hundreds have died in the bombing campaign that began Sept. 19. Some 275,000 civilians remain in the area. The army says rebels have been using them as human shields.