National security adviser John Bolton at a press conference in Moscow this month. (Sergei Ilnitsky/EPA-EFE/Shutterstock)

The United States is “right now undertaking offensive cyber operations” to safeguard next week’s midterm elections, though it was “too soon to tell” whether they are having an effect, White House national security adviser John Bolton said Wednesday.

Though Bolton did not specify the operation’s nature, U.S. Cyber Command has begun signaling to Russian operatives that their identities are known — an implicit warning not to attempt to disrupt American politics. The Washington Post and other media reported on those developments last week.

The offensive cyber actions were aimed at “defending the integrity of our electoral process . . . and our adversaries [had] better know that and better understand that,” said Bolton, speaking in Washington at an event sponsored by the Alexander Hamilton Society.

In remarks afterward, Bolton confirmed that the offensive activity fell below the level of armed conflict — it does not result in death, damage or destruction — in that it did not “require the type of sign-off” from senior officials that would normally precede the use of military force. The White House, Bolton noted, recently eased rules governing offensive cyber operations.

Whether such signaling amounts to an offensive cyber operation depends on the method used, analysts said. Simply sending a text message or email would not, said Kate Charlet, a former senior Pentagon cyber official. But “if you had a banner or a pop-up on an adversary’s computer that says, ‘We’re watching you,’ that would be cyber-enabled,” she said, noting that she was not briefed on the operation.

Brett Bruen, a former National Security Council official who has worked on countering Russian disinformation, called signaling “a pretty ineffective” warning shot. “What we have seen over recent months have been largely superficial steps, mostly for domestic consumption, to be able to say that we are doing something,” he said.

CyberCom’s action by itself “is not going to be the linchpin that gets the Russians to stand down, but it is a reasonable component” of a larger strategy to change behavior, said Charlet, now at the Carnegie Endowment for International Peace.

The operation is an early use of a new presidential directive — National Security Presidential Memorandum 13 — that Bolton said minimizes the “procedural restrictions on undertaking offensive cyber operations.” Said Bolton: “The objective here is not to have unrestricted cyberwarfare. The objective is to create structures of deterrence by making our adversaries understand that when they engage in offensive cyberactivity themselves, they will bear a disproportionate cost.”

Bolton also said Wednesday that in the near term, the U.S. defense budget is going to flatten, forcing the Pentagon to cut costs while executing a military buildup designed to counter Russia and China.

President Trump ordered agencies across his administration to slash 5 percent from their budget proposals for the coming fiscal year. The order came in response to a 17 percent increase in the federal budget deficit for fiscal 2018, the largest jump since 2012, which resulted from the tax cut he approved late last year and increased government spending.

Bolton said the cuts would have to come from discretionary spending pools, such as the defense budget, rather than from entitlement spending funds, such as Medicare and Social Security.

That presents a challenge to Defense Secretary Jim Mattis, who received a sizable spending increase last year and was counting on the fiscal 2020 budget to make fundamental investments enabling the military to take on Russia and China rather than terrorist insurgencies.

Bolton said procurement reform and cost-cutting should target unnecessary initiatives, even as priorities for a military buildup receive more funding. “In the Reagan years, when there was a big defense buildup, there was perhaps not so much emphasis on cost-cutting and taking cost out — I think that is a difference here,” he said. “So, hopefully, although the budget may not be in an upward curve, the effective spending of the money will increase.”

Deputy Defense Secretary Patrick M. Shanahan said Friday that the Trump administration has instructed the Pentagon to prepare a $700 billion budget for 2020. The Pentagon had planned on a budget of $733 billion.

Bolton characterized the cuts as a matter of economic and national security.

“It is a fact that when your national debt gets to the level ours is, that constitutes an economic threat to the society, and that kind of a threat ultimately has a national security consequence for it,” he said. “It just has to be that we can constrain government spending in ways that allow us to spend on the priorities that we need to.”