WASHINGTON – It has the makings of a new Cold War, or worse.

The deep chill in U.S.-Russian relations is stirring concern in some quarters that Washington and Moscow are in danger of stumbling into an armed confrontation that, by mistake or miscalculation, could lead to nuclear war.

American and European analysts and current and former U.S. military officers say the nuclear superpowers need to talk more. A foundational arms control agreement is being abandoned and the last major limitation on strategic nuclear weapons could go away in less than two years. Unlike during the Cold War, when generations lived under threat of a nuclear Armageddon, the two militaries are barely on speaking terms.

“During the Cold War, we understood each other’s signals. We talked,” says the top NATO commander in Europe, U.S. Army Gen. Curtis Scaparrotti, who is about to retire. “I’m concerned that we don’t know them as well today.”

Scaparrotti, in his role as Supreme Allied Commander Europe, has met only twice with Gen. Valery Gerasimov, the chief of the Russian general staff, but has spoken to him by phone a number of other times.

“I personally think communication is a very important part of deterrence,” Scaparrotti said, referring to the idea that adversaries who know each other’s capabilities and intentions are less likely to fall into conflict. “So, I think we should have more communication with Russia. It would ensure that we understand each other and why we are doing what we’re doing.”

He added: “It doesn’t have to be a lot.”

The United States and Russia, which together control more than 90 percent of the world’s nuclear weapons, say that in August they will leave the 1987 treaty that banned an entire class of nuclear weapons. And there appears to be little prospect of extending the 2010 New Start treaty that limits each side’s strategic nuclear weapons.

After a period of post-Cold War cooperation on nuclear security and other defense issues, the relationship between Washington and Moscow took a nosedive, particularly after Russian forces entered the former Soviet republic of Georgia in 2008. Tensions spiked with Russia’s annexation of the Crimea in 2014 and its military intervention in eastern Ukraine. In response, Congress in 2016 severely limited military cooperation with Russia.

The law prohibits “military-to-military cooperation” until the secretary of defense certifies that Russia “has ceased its occupation of Ukrainian territory” and “aggressive activities.” The law was amended last year to state that it does not limit military talks aimed at “reducing the risk of conflict.”

Relations frayed even further amid U.S. allegations that Russia interfered in the 2016 U.S. presidential election, although President Donald Trump has doubted Russian complicity in what U.S. intelligence agencies assert was an effort by Moscow to boost Trump’s chances of winning the White House. After a Helsinki summit with Putin in July, Trump publicly accepted the Kremlin leader’s denial of interference.

Marine Gen. Joseph Dunford, chairman of the Joint Chiefs of Staff, said in an interview Friday that Russian behavior is to blame for the strained relationship.

“It’s very difficult for us to have normal relationships with a country that has not behaved normally over the last few years,” Dunford said. “There are major issues that affect our bilateral relationship that have to be addressed, to include where Russia has violated international laws, norms and standards.”

Dunford said he speaks regularly with Gerasimov, his Russian counterpart, and the two sides talk on other levels.

“I’m satisfied right now with our military-to-military communication to maintain a degree of transparency that mitigates the risk of miscalculation,” he said. “I think we have a framework within to manage a crisis, should one occur, at the senior military-to-military level.”

James Stavridis, a retired Navy admiral who was the top NATO commander in Europe from 2009 to 2013, says the West must confront Russia where necessary, including on its interventions in Ukraine and Syria. But he believes there room for cooperation on multiple fronts, including the Arctic and arms control.

“We are in danger of stumbling backward into a Cold War that is to no one’s advantage,” he said in an email exchange. “Without steady, political-level engagement between the defense establishments, the risk of a true new Cold War rises steadily.”

No one is predicting a deliberate Russian act of war in Europe, but the decline in regular talks is a worry to many.

Moscow says it is ready to talk.

“Russia remains open for interaction aimed at de-escalating tension, restoring mutual trust, preventing any misinterpretations of one another’s intentions, and reducing the risk of dangerous incidents,” the Russian Ministry of Foreign Affairs said in a statement last week in response to NATO’s 70th anniversary celebration.

Sam Nunn, who served in the Senate as a Democrat from Georgia from 1972 to 1997, argues that dialogue with Russia is too important to set aside, even if it carries domestic political risk.

“You can’t call time out,” he said in an interview. “The nuclear issues go on, and they’re getting more dangerous.”

Nunn co-wrote an opinion piece with former Secretary of State George Shultz and former Defense Secretary William Perry arguing that the U.S. and its allies and Russia are caught in a “policy paralysis” that could lead to a military confrontation and potentially the first use of nuclear weapons since the U.S. bombed Japan in August 1945.

“A bold policy shift is needed,” they wrote in the Wall Street Journal on Thursday, “to support a strategic re-engagement with Russia and walk back from this perilous precipice. Otherwise, our nations may soon be entrenched in a nuclear standoff more precarious, disorienting and economically costly than the Cold War.”

A group of U.S., Canadian, European and Russian security experts and former officials in February issued a call for talks with Russia on crisis management.

“The risks of mutual misunderstanding and unintended signals that stem from an absence of dialogue relating to crisis management … are real,” the Euro-Atlantic Security Leadership Group said in a statement.

It said this could lead to conventional war with Russia or, in a worst case scenario, “the potential for nuclear threats, or even nuclear use, where millions could be killed in minutes.”