Over the past year, reports have circulated of widespread cyberattacks, based in China, against American corporate, media, and infrastructure targets. Now it’s being learned that cyberespionage efforts extended to the 2008 US presidential election, and appear to have been backed by the Chinese government, according to former Obama national intelligence chief Dennis Blair. The disclosure was made the day before President Obama and Prime Minister Xi Jinping meet this weekend at the Sunnylands estate in California, writes NBC News. The hacking is reported to have focused on the Obama and McCain camps’ respective stances on China, and exfiltrated large amounts of internal data including position papers and private emails.

Obama previously disclosed the attacks in 2009

NBC points out that Obama previously disclosed the attacks in loose terms in 2009, saying that "hackers gained access to emails and a range of campaign files," without divulging where the attacks originated. The efforts to access confidential data were reportedly sustained for months after an email phishing attack gave the hackers access to party networks.

Private email to Taiwanese president Ma Ying-jeou

We're now learning that the McCain camp was similarly attacked. One piece of information reported to have been acquired is a private email from then-presidential candidate John McCain to Taiwanese president Ma Ying-jeou supporting the country’s efforts to modernize its military. Afterward, a McCain adviser reported being contacted by a senior Chinese diplomat about the correspondence — putting him "on notice" that China knew what was going on.

In addition to this weekend's talks in California, the ongoing cyberattacks will be at the top of the list for discussion at next month's Strategic and Economic Dialogue meeting between the countries' top diplomats. But government officials are skeptical about the prospect for speedy progress given the economic incentives at play and China's continued insistence that it's not to blame. By starting a dialogue, it's hoped that the nations can agree to standards of behavior, but that horizon could be far down the road.