The Obama administration has officially accused Russia of orchestrating a hacking campaign aimed at interfering in the U.S. election. A joint statement from the Department of Homeland Security and the Director of National Intelligence states that “the recent disclosures of alleged hacked e-mails on sites like DCLeaks.com and WikiLeaks and by the Guccifer 2.0 online persona are consistent with the methods and motivations of Russian-directed efforts,” noting that similar tactics have been used by Russia in other countries. It also states that “based on the scope and sensitivity of these efforts, that only Russia’s senior-most officials could have authorized these activities.”

The statement also notes recent evidence of scanning and probing of election systems themselves in some states, but says that “we are not now in a position to attribute this activity to the Russian government,” and that actually altering ballot counts or election results by cyber attack would be “extremely difficult.” It doesn’t explicitly say what electoral outcome these activities are aimed at producing, but given the targets, the implication that the Kremlin is intervening on behalf of Donald Trump is pretty clear.

U.S. officials have discussed these activities before but have avoided explicitly blaming Russia for them. (Anonymous quotes are another story.) This reluctance, which has reportedly angered some staffers in the White House and State Department, was likely motivated in part by hopes that meaningful dialogue was still possible with Russia on a range of international crises, notably the war in Syria. As I wrote earlier this week, after the U.S. suspended talks with Russia over a cease-fire in Syria and Vladimir Putin pulled Russia out of longstanding nuclear agreements in response, there’s no longer a whole lot of cooperation left to preserve.

We’re in uncharted waters now, and it’s not quite clear what comes next: Just making an allegation like this is pretty unprecedented. One thing we can be fairly certain of is that the Russian government will completely deny the whole thing and that the Trump campaign will accuse the Obama administration of drumming up a phony conspiracy to help Hillary Clinton … at least, until Trump decides to encourage Russia to do more of it.