In October, the Department of Homeland Security and the Office of the Director of National Intelligence released a joint statement blaming the Russian government for hacking the DNC. In it, they state their attribution plainly:
The U.S. Intelligence Community (USIC) is confident that the Russian Government directed the recent compromises of e-mails from US persons and institutions, including from US political organizations. 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. These thefts and disclosures are intended to interfere with the US election process.
What’s missing is any evidence at all. If this federal confidence is based on evidence that’s being withheld from the public for any reason, that’s one thing — secrecy is their game. But if the U.S. Intelligence Community is asking the American electorate to believe them, to accept as true their claim that our most important civic institution was compromised by a longtime geopolitical nemesis, we need them to show us why.