Since the first American shipments of sophisticated weapons to Ukraine, President Biden has never wavered on one prohibition: President Volodymyr Zelensky had to agree to never fire them into Russian territory, insisting that would violate Mr. Biden’s mandate to “avoid World War III.”
But the consensus around that policy is fraying. Propelled by the State Department, there is now a vigorous debate inside the administration over relaxing the ban to allow the Ukrainians to hit missile and artillery launch sites just over the border in Russia — targets that Mr. Zelensky says have enabled Moscow’s recent territorial gains.
The proposal, pressed by Secretary of State Antony J. Blinken after a sobering visit to Kyiv last week, is still in the formative stages, and it is not clear how many of his colleagues among Mr. Biden’s inner circle have signed on. It has not yet been formally presented to the president, who has traditionally been the most cautious, officials said.
The State Department spokesman, Matthew A. Miller, declined to comment on the internal deliberations over Ukraine policy, including Mr. Blinken’s report after his return from Kyiv.
But officials involved in the deliberations said Mr. Blinken’s position had changed because the Russians had opened a new front in the war, with devastating results. Moscow’s forces have placed weapons right across the border from northeastern Ukraine, and aimed them at Kharkiv — knowing the Ukrainians would only be able to use non-American drones and other weaponry to target them in response.
For months, Mr. Zelensky has been mounting attacks on Russian ships, oil facilities and electricity plants, but he has been doing so largely with Ukrainian-made drones, which don’t pack the power and speed of the American weapons. And increasingly, the Russians are shooting down the Ukrainian drones and missiles or sending them astray, thanks to improved electronic warfare techniques.
Now, the pressure is mounting on the United States to help Ukraine target Russian military sites, even if Washington wants to maintain its ban on attacking oil refineries and other Russian infrastructure with American-provided arms. Britain, usually in lockstep with Washington on war strategy, has quietly lifted its own restrictions, so that its “Storm Shadow” cruise systems can be used to target Russia more broadly.
The British foreign secretary, David Cameron, a former prime minister, said during a visit to Kyiv ahead of Mr. Blinken’s that Ukraine “absolutely has the right to strike back at Russia.”
The United States is now considering training Ukrainian troops inside the country, rather than sending them to a training ground in Germany. That would require putting American military personnel in Ukraine, something else that Mr. Biden has prohibited until now. It raises the question of how the United States would respond if the trainers, who would likely be based near the western city of Lviv, came under attack. The Russians have periodically targeted Lviv, though it is distant from the main areas of combat.
Another hint of a shift came in recent days. Secretary of Defense Lloyd J. Austin III, in repeating the usual administration position — “our expectation is that they continue to use the weapons that we’ve provided on targets inside of Ukraine” — seemed to suggest that there may be exceptions made for Russian aircraft operating in the safety of Russian territory, just over the border, enabling pilots to release glide bombs into eastern Ukraine.
“The aerial dynamic’s a little bit different,” Mr. Austin allowed, but he struggled to articulate the new standard. “And so — but again, don’t — don’t want to speculate on any — any one or — or any type of engagement here at the podium, so.”
When a reporter followed up by asking whether such aerial operations by the Russians were “off-limits or not off-limits?” Mr. Austin did not respond.
The Russians are accustomed to such debates, and they have been unsubtle in playing to American concerns about an escalation of the war.
This week they began very public exercises with the units that would be involved in the use of tactical nuclear weapons, the kind that would be used on Ukrainian troops. Russian news reports said it was “a response to provocative statements and threats from Western officials against Russia.”
But the administration appears less sensitive to such threats than it was in the early days of the war, or in October 2022, when there were fears that Russia, its forces failing, might use those weapons against Ukrainian military targets. During that incident, some administration officials, picking up conversations among Russian officers, feared there was a 50 percent chance a nuclear weapon could be detonated.
The current exercises, in contrast, are being dismissed as bluster and muscle-flexing.
In a notable break from the administration’s public position, Victoria Nuland, who left her position as No. 3 official in the State Department this spring, is now making a public argument that the administration needs to drop its ban on the use of its weapons against targets inside Russia.
“I think if the attacks are coming directly from over the line in Russia, that those bases ought to be fair game, whether they are where missiles are being launched from or where they are where troops are being supplied from,” she said Sunday on ABC’s “This Week.”
“I think it’s time for that because Russia has obviously escalated this war,” she added, noting that Russia’s attack on Kharkiv is an effort “to decimate it without ever having to put a boot on the ground. So I think it is time to give the Ukrainians more help hitting these bases inside Russia.”
Ms. Nuland was always among a far more hawkish camp inside the administration, and her view was in the minority. But over time she won more and more of the arguments over whether to send more sophisticated missiles and artillery systems to Ukraine, and each time Mr. Biden relented, the worst fears he had about escalation did not materialize.
In an interview with The New York Times this week, Mr. Zelensky dismissed fears of escalation, saying President Vladimir V. Putin of Russia had already escalated the war. And he thought it unlikely that Mr. Putin would ever make good on his threat to unleash a nuclear weapon.
Mr. Biden and some of his aides are clearly not convinced. Over the past year they have said they believe there is some red line out there that would unleash a more severe reaction from Mr. Putin. They just don’t know exactly where that is, or what the reaction might be.
In private with Mr. Blinken last week and in his interview with The Times, Mr. Zelensky argued that at this desperate stage of the war, it was critical to let him use American weapons against Russian military units.
“This is part of our defense,” Mr. Zelensky told The Times. “How can we protect ourselves from these attacks? This is the only way.”