News Analysis

WASHINGTON >> Donald Trump often says he never wants to signal to the nation’s adversaries what he would do as commander in chief — an embrace of the concept of “strategic ambiguity” that is as old as warfare.

But on the critical question of whether the United States should ever be the first to use nuclear weapons, he appeared somewhere between contradictory and confused during his debate with Hillary Clinton on Monday.

On a related issue that Trump raised himself — the modernization by the Russians of their nuclear arsenal at a time when the United States is still debating plans and looking for the money — he had the gist of it right. The implication of his observation was that the U.S. had to match what the Russians were doing, creating the specter of a new arms race; Clinton hinted at that too, but in the arena of cyberweapons.

Questions about Trump’s philosophy on the use of nuclear weapons have shadowed him throughout the campaign, in part because Clinton has repeatedly raised them to sow doubts that he has the temperament for a job in which he would have sole authority over the world’s most powerful arsenal.

The nuclear issue arose when the moderator, Lester Holt, noted that President Barack Obama “reportedly considered changing the nation’s long-standing policy on first use,” which has left open the option that the U.S. would be the first to detonate a nuclear weapon in a conflict, as it did at Hiroshima 71 years ago. After lengthy debate inside the administration, Obama appears unlikely to alter that policy before leaving office.

“Do you support the current policy?” Holt asked.

In the past, the word “nuclear” has touched off many reactions from Trump, from descriptions of the decrepit state of some of the United States’ nuclear forces, to denunciations of the Iranian nuclear deal, to descriptions of a long-dead uncle who taught at the Massachusetts Institute of Technology and warned Trump decades ago about the power of nuclear weapons.

Trump touched on most of those — except the uncle — Monday night, but seemed to come down on both sides of the nuclear-first-use debate.

“I would certainly not do first strike,” Trump first declared, appearing to be advocating a change in U.S. policy that dates to the Truman administration.

But he did not stick with it.

“I think that once the nuclear alternative happens, it’s over,” Trump said. “At the same time, we have to be prepared. I can’t take anything off the table.”

That put him pretty much where Obama ended up after 7 1/2 years. The president vowed to reduce the role of nuclear weapons in U.S. strategic planning, and he did.

It was not the first time Trump had been asked about nuclear first-use, or the first time he had offered an obfuscated answer. When the subject came up in an interview in July, he said, “I would only make that commitment as the agreement is being signed,” although it was not clear what agreement he had in mind. “I wouldn’t want to play my cards. I don’t want to say that.”

When pressed, he added: “I will do everything in my power never to be in a position where we will have to use nuclear power. It’s very important to me.”

The Trump campaign did not respond to several emails seeking to clarify Trump’s response at the debate. Clinton, his Democratic opponent, never addressed the question when she was asked for a response to Trump’s answer.

While Trump argues that he would be reluctant to use nuclear weapons, he certainly does not sound reluctant to build them. He argued for a resumption of the arms race.

“Russia has been expanding their — they have a much newer capability than we do,” he said. “We have not been updating from the new standpoint.”

His observation is correct — the Russians have been deploying new nuclear arms at a brisk pace, while the United States is devising, but not yet executing, a nuclear modernization program that Obama put on the drawing board. But Obama is leaving the largest investments — upward of 1 trillion dollars in coming decades — for his successors.

In testimony before Congress in July, Franklin C. Miller, a nuclear expert who has served several presidents over 31 years, said that “Russia is engaged in a massive modernization of its nuclear forces,” deploying two new types of intercontinental ballistic missiles and submarine-launched ballistic missiles, while launching new nuclear-armed submarines and building new heavy bombers.

He was on shakier ground when he and Clinton turned to to the newest class of weapons, cyberweapons. And on that issue, Clinton sounded more hawkish than Trump.

Clinton went right at Russia, arguing that its president, Vladimir Putin, “is playing a really tough, long game here,” taunting Trump by reminding him he had encouraged Russian hackers to attack the United States. (He actually invited them to hack her emails.)

She accused Russia of having been the force behind the theft of data from the Democratic National Committee and, in a veiled swipe at the Obama administration, suggested that it had not been tough enough in calling out that behavior.

“We need to make it very clear — whether it’s Russia, China, Iran or anybody else — the United States has much greater capacity,” she said. “And we are not going to sit idly by and permit state actors to go after our information, our private-sector information or our public-sector information.”

Then she added: “We don’t want to use the kinds of tools that we have. We don’t want to engage in a different kind of warfare. But we will defend the citizens of this country.”

In fact, as Clinton knows, the United States employed cyberweapons against Iran’s nuclear program when she was secretary of state. Since she left office, they have been used again, against the Islamic State.

Trump made no acknowledgment of the U.S. offensive cyberarsenal and continued to cast doubt whether Russia was behind the attack on the Democratic committee, saying it could have been the Chinese or “somebody sitting on their bed that weighs 400 pounds.” He blamed Obama because “we’ve lost control of things we used to have control over.”