The U.S. and other world leaders issued a joint declaration condemning Russia's war in Ukraine and threatening not to use nuclear weapons, an intimidation tactic that has become commonplace for Russian President Vladimir Putin since launching his invasion nine months ago.

The use or threat of use of nuclear weapons is against the law. Efforts to address crises, as well as diplomacy and dialogue, are important. The era of today should not be of war.

The document marks a victory for the Biden Administration and global allies, who wanted to end this year's summit in Indonesia with a statement censuring Russia for its unprovoked military campaign in Ukraine. The Biden team has launched a discreet, multi-pronged effort to pressure Moscow to dial back the increasingly reckless bluster that has sparked fears the world was nearing the brink of nuclear war. Through a series of one-on-one discussions and back channels between top U.S. and Russian officials, the Administration has worked to get Putin and his government to stop threatening the use of nuclear weapons.

In a rare disclosure on Monday, the White House revealed that the CIA Director William Burns met with his Russian counterpart Sergey Naryshkin in Ankara to discuss the costs of using a nuclear weapon in the Ukraine conflict. The White House said that he was not conducting negotiations. There are consequences of the use of nuclear weapons by Russia and the risk of strategic stability.

On the same day, the presidents of the US and China issued a joint statement saying that nuclear weapons should not be used. The rebuke was noteworthy because Beijing has tacitly approved of Putin's actions and shown reluctance to join the international community in condemning invasion.

The United States has a strategy for nuclear threats from China and Russia.

If Moscow goes nuclear in Ukraine, the U.S. will experience further economic and diplomatic isolation. There are indications that the strategy, which has gathered traction behind the scenes since late September after Putin illegally annexed four occupied regions ofUkraine, may be working. Putin said Russia wouldn't gain anything from a nuclear strike. He said at the conference that there was no need for it. There is no point in that.

Observers are cautiously optimistic that the U.S. approach will draw Putin away from the nuclear threshold, but they are worried about the instability of relations between the world's foremost nuclear powers. The Biden team has warned Putin not to cross the nuclear line and encouraged other countries to do the same. Lynn Rusten is the vice president at the Nuclear Threat Initiative and was a senior official at the White House and State Department. They need to stay alert. The risk of nuclear use will not go away as the war continues.

The threat of the world's most powerful weapon being detonated cannot be ignored, despite the fact that U.S. intelligence has yet to observe changes in Russia's strategic arsenal. Since the beginning of the war, Biden has sought to avoid a nuclear war with Russia. Around 90 percent of the world's nuclear warheads are owned by Russia and the United States, and these arsenals loom large over U.S. strategy.

The Administration wanted to strike a balance between supporting Ukraine with weapons and intel information and avoiding a war with Russia. At every turn in the conflict, the Biden team has had to adapt their strategy and figure out how far the U.S. can go without crossing Putin's red lines.

The military test launch of an intercontinental missile was put off due to fears that Russia would view it as threatening. The U.S. turned down a proposal to give the Ukrainian Air Force with fighter jets. The President decided against establishing a no-fly zone because it would bring American pilots into combat with Russians. Biden did not engage in nuclear threats in response to Putin.

There is a $100 billion mission tomodernize America's aging nuclear missiles.

Jake Sullivan, Biden's National Security Adviser, has told Russian officials the consequences of a nuclear strike in Ukraine. Since 1945, when the U.S. dropped two atomic bombs on Japan, the Administration has refused to reveal what penalties Russia would face if it used a nuclear weapon.

George Perkovich is the vice president for studies at the Carnegie Endowment for International Peace, a Washington non-profit organization. He said it was still early. We aren't at a point where the risk of Russia using nukes is zero.

Over the last several months, the Russian military has suffered a number of embarrassing defeats in Ukraine and last week withdrew from the area west of the Dnipro River. The danger of a larger, more calamitous confrontation with the West will rise if Putin's forces continue to be bogged down fighting a smaller Ukrainian army. The winter weather may open the way for peace talks between Russia and the Ukrainians.

The last time the world was near a nuclear war was in 1962, when the Cuban missile crisis took place. 60 years ago, the showdown did not develop into a shooting war. Can we come up with a diplomatic solution to the disaster? Russia is bombarding Ukrainian cities and there is a lot of violence in that country. Lessons of the past must be reexamined in order to survive.

Despite being sworn adversaries, the U.S. and Soviet Union established several treaties after the Cuban missile crisis. The road we are on right now has a lot of curves. I don't know if we'll make it, but we should try.

W. J. Hennigan can be reached at william.hennigan@time.com.