The United States has no nuclear hotline to Beijing. The two countries have never had an in-depth, serious conversation about American missile defenses in the Pacific, or China’s experiments to blind U.S. satellites in time of conflict.

And Chinese officials have consistently rejected the idea of entering arms control talks, shutting down such suggestions by noting — accurately — that the United States and Russia each have deployed five times more nuclear warheads than Beijing possesses.

President Biden is seeking to change all that.

For the first time, the United States is trying to nudge China’s leadership into a conversation about its nuclear capability. U.S. officials, describing the American strategy, say Mr. Biden and his top aides plan to move slowly — focusing the talks first on avoiding accidental conflict, then on each nation’s nuclear strategy and the related instability that could come from attacks in cyberspace and outer space.

Finally — maybe years from now — the two nations could begin discussing arms control, perhaps a treaty or something politically less complex, such as an agreement on common norms of behavior.

In Washington, the issue has taken on more urgency than officials are acknowledging publicly, according to officials who are involved. Mr. Biden’s aides are driven by concern that a new arms race is heating up over hypersonic weapons, space arms and cyberweapons, all of which could unleash a costly and destabilizing spiral of move and countermove. The fear is that an attack that blinded space satellites or command-and-control systems could quickly escalate, in ways that were not imaginable in the nuclear competitions of the Cold War. China’s capabilities could also pose a threat to President Biden’s hopes of reducing the role of nuclear weapons in American defenses.

In some ways, Washington is focused on the progress of China’s nuclear capability in a way that it has not been since Mao first tested a weapon in 1964.

In his virtual summit meeting earlier this month with Xi Jinping, China’s president, who clearly has sought to present himself as a epoch-defining leader alongside Mao, Mr. Biden raised what the White House has euphemistically called “strategic stability talks.”

In interviews, Mr. Biden’s aides have said the effort is a tentative first step toward a far larger agenda, akin to the initial conversations about nuclear weapons that Russia and the United States held in the 1950s. The starting goal, they insist, is to simply avoid miscommunication and accidental war — even if it never rises to the level of a nuclear threat.

“You will see at multiple levels an intensification of the engagement to ensure that there are guardrails around this competition,” Jake Sullivan, Mr. Biden’s national security adviser, said in a presentation at the Brookings Institution the day after the virtual summit.

The nuclear relationship with Russia, he noted, is “far more mature, has a much deeper history to it.” After the summit meeting between Mr. Biden and Mr. Xi, he added, it is time to begin such conversations with China. “It is now incumbent on us to think about the most productive way to carry it forward,” he said.

In a sense, this is the revival of an old fear in Washington: In 1964, Lyndon Johnson was so worried about the rise of another nuclear rival that he considered, but ultimately rejected, plans to conduct a pre-emptive strike or covert sabotage on China’s main nuclear testing site at Lop Nor.

But China’s decision to maintain a “minimum deterrent” for the past six decades — a nuclear force large enough to assure that it could respond to a nuclear attack, but not nearly the size of America’s or Russia’s — largely knocked its nuclear program off the Pentagon’s list of top threats. Now, its recent moves, from building new missile silo fields to testing new types of advanced weapons, come just as Mr. Biden’s aides are deep into an examination of American nuclear strategy that will be published in coming months.

The review, which every new administration is required to undertake in its first year or so, will contain key decisions — including whether to go ahead with a modernization plan that by the last comprehensive estimate, four years ago, looked likely to cost 1.2 trillion dollars over the next 30 years. The future of those plans has been the subject of furious lobbying campaigns, especially among the nation’s top defense contractors.

Earlier this month the Pentagon concluded that the size of the Chinese nuclear arsenal may triple by 2030, to upward of 1,000 warheads. But the administration’s concern is not just the number of weapons — it is the new technology, and particularly how Chinese nuclear strategists are thinking about nontraditional arms.

When the Chinese launched a hypersonic missile in July, circling the globe once and then deploying a maneuverable glide vehicle that could zig and zag on an unpredictable path and deliver a weapon anywhere on earth, Gen. Mark A. Milley, the chairman of the Joint Chiefs of Staff, declared that the U.S. was “very close” to a “Sputnik moment.” But in the weeks since, American officials have been reluctant to say what, exactly, about that experiment so rattled them — beyond the fact that it revealed a technological sophistication that they did not know the Chinese had achieved.

The hypersonic nature of the missile — meaning it can move at more than five times the speed of sound — was the least interesting element of the test. All nuclear missiles go at least that fast. But the stubby glider it released — which could hold a nuclear warhead — was designed to evade the United States’ primary missile interceptors, which can operate only in outer space. (In recent weeks, the Pentagon issued a contract for design work on technology to intercept the gliders, but that would be years away.)

It’s unclear whether China plans to deploy a hypersonic weapon in the future, and, even if it does, whether they would be armed with nuclear warheads. But General Milley’s deputy, Gen. John Hyten, who is retiring as the vice chairman of the Joint Chiefs, told reporters in October that the Chinese military had conducted “hundreds” of hypersonic tests, compared with nine by the United States.

General Hyten said the test, combined with Beijing’s other moves, such as digging hundreds of new silos for long-range missiles, suggest the Chinese government may now be interested in developing a nuclear first-strike capability, not just the minimum deterrent.

“Why are they building all of this capability?” he asked on CBS News. While it is not clear what Chinese strategists intend, he said, the hypersonic glide vehicle appears to be “a first-use weapon.”

Inside the White House and the Pentagon, there is no unanimity on that point. Mr. Biden has long been wary of assessments that could be intended to drive up the Pentagon’s budget — and certainly American defense contractors, their executive offices jammed with former senior military officers, have a vested interest in describing a new threat that could lead to billions of dollars in new investments.

But even some skeptics agree that the Chinese hypersonic test, along with antisatellite technologies that could blind American early-warning and command-and-control systems, suggest a major rethinking of American nuclear strategy and plans is overdue.

Gen. John Raymond, who commands the newly created United States Space Force, recently told New York Times reporters and editorial writers that in the case of a crisis, he has no direct channel for communicating with his Chinese counterpart — a dangerous situation if, for instance, an accidental collision with a Chinese spacecraft were to be misperceived as an act of aggression.

That appeared to be at the core of Mr. Sullivan’s first concern: establishing lines of communication between the two militaries, of the kind the United States and Russia have had for decades. (He avoided the use of the word “nuclear” in his talk, a reflection of how space, cyberweapons and other high technologies need to be part of the conversation, Mr. Biden’s senior aides say.)

On Capitol Hill, the conversation so far is largely about matching the Chinese investment, rather than rethinking the nature of the arms race.

“I’m very concerned,” Rose Gottemoeller, an arms control official in several administrations who now teaches at Stanford University, said in an interview. “What’s worrying me is the automaticity of the actions — of more nuclear weapons and more missile defenses without thinking if there’s a smarter way.”

Mr. Xi and Mr. Biden, American officials said, agreed to further conversations — but there was no commitment on how deep those would go. Asked whether the talks would include the topic of arms control, the National Security Council, in a statement, said, “No. What we are seeking — and what Jake Sullivan spoke about — are conversations with empowered interlocutors” about “guardrails to reduce risk or the chance of miscalculation.”

The history of those conversations is not encouraging. For years, across several administrations, the United States tried to get Chinese officials to talk about how they would secure nuclear weapons in North Korea if the nation collapsed. The effort was to avoid a collision among Chinese, South Korean and American forces seeking to find and secure loose weapons. The Chinese have always demurred, perhaps for fear of being caught talking about the possibility of the North’s collapse.

It is possible, many arms control experts say, that the Chinese buildup is motivated by the deployment of U.S. missile defenses in the Pacific — land-based systems in California, Alaska, Guam and South Korea, and aboard ships patrolling off Japan and the Korean Peninsula. The U.S. has always insisted that these systems are designed to deter North Korea. But the Chinese government has long voiced worries that North Korea’s nuclear program provides a convenient excuse for the United States to build a system aimed at containing Chinese nuclear weapons.

China and the United States have never engaged in a detailed discussion of missile defenses in the Pacific. But the hypersonic test may force the issue, independent experts say, because it is clear Beijing’s ambitions are expanding.

Even before the test, American officials and military contractors were trying to figure out new defenses against the hypersonic warheads. That would be more complex than intercepting an intercontinental ballistic missile, a project that has already cost more than $300 billion over several decades and yielded only episodic success. This month, Raytheon, Northrop and Lockheed won Pentagon awards to compete with one another in building an interceptor seen as agile enough to knock out a hypersonic glider. The defensive weapon is billed as the first of its kind.

The Pentagon also has embarked on a vast effort to loft up to 500 satellites that would provide improved means of tracking ballistic, cruise and hypersonic missiles. The swarm is considered crucial for establishing an end-to-end system that would identify hypersonic attacks and direct interceptors onto flight paths that would let them destroy the incoming gliders.

It all worries Ms. Gottemoeller, who recently published a memoir of negotiating the New Start treaty with Russia. “This action-reaction cycle is in nobody’s interest,” she said. “We have to talk about how we’re going to interrupt it.”