WASHINGTON -- A massive leak of Democratic leadership e-mails has sent the party reeling into its national convention this week, with aides to Hillary Clinton, its presumptive presidential nominee, accusing Russia of coordinating the attack.Robby Mook, campaign manager for Hillary for America, accused Moscow on Sunday of deliberately helping Republican presidential nominee Donald Trump by directly orchestrating the hack, which resulted in the release of roughly 20,000 e-mails by Wikileaks, a whistleblower organization founded by Julian Assange, on Friday.Several of those e-mails reveal an apparent bias within the Democratic National Committee for Clinton during her primary campaign against Bernie Sanders, the independent senator from Vermont, who for months claimed the process was stacked in her favor.Sanders renewed his call on Sunday for the resignation of Debbie Wasserman Schultz, chair of the DNC and the party's most senior Jewish member. In her own e-mail exchanges, Wasserman Schultz questioned Sanders' loyalty to the party– he has never registered as a Democrat– and disparaged his campaign's leadership in personal terms.As a result of the leak, Wasserman Schultz announced her resignation on Sunday night.The leak also showed the party's chief financial officer sought to promote a media narrative that Sanders had "skated" on his "Jewish heritage," and suggested that his lack of religiosity would be a political weakness."I am not an atheist, but aside from all of that, it is an outrage and sad," Sanders said in response on Sunday in an interview with CNN. "The DNC was supporting Hillary Clinton, and was in opposition to our campaign."For its part, Wikileaks accused its critics over the weekend of being disproportionately Jewish in a series of messages sent over its Twitter account."Tribalist symbol for establishment climbers?," one message asked. "Most of our critics have 3 (((brackets around their names))) and have black-rim glasses. Bizarre."Brackets have recently been utilized by Jewish figures on Twitter seeking to stand up publicly to anti-Semitic trolls on the platform, who have for years used the marker to identify Jews for harassment. Wikileaks deleted the tweets hours after posting.Their leak disrupted a party still struggling to unify– just in time for the Democratic National Convention to convene on Monday in Philadelphia. The timing is no coincidence, Mook said."What's disturbing to us is that experts are telling us that Russian state actors broke into the DNC, stole these e-mails," Mook charged, "and other experts are now saying that the Russians are releasing these e-mails for the purpose of helping Donald Trump."The DNC first reported in June that "Russian-backed" agents had invaded its system. At the time, the party called in cybersecurity firm CrowdStrike, among other independent experts, to handle the breach.In its investigation, CrowdStrike identified "two sophisticated adversaries on the network"– codenamed Cozy Bear and Fancy Bear– with "operational security second to none" and considered "some of the best adversaries out of all the numerous nation-state, criminal and hacktivist/terrorist groups we encounter on a daily basis.""Both adversaries engage in extensive political and economic espionage for the benefit of the government of the Russian Federation and are believed to be closely linked to the Russian government’s powerful and highly capable intelligence services," the firm reported.The proximity of that Russian hack to Friday's Wikileaks dump– of the very same material accessed by the Russians– appears to be undergirding Democratic concerns. If true, Moscow's hacking effort is just one more piece of evidence, piled increasingly high, that Russian leadership supports Trump's bid for president.Trump has filled his inner circle with aides who have long worked in Russian politics and, consequentially, within the orbit of Russian President Vladimir Putin, who has repeatedly offered praise for the GOP nominee. And the Trump Organization relies heavily on Russian money, which since the 1990s has disproportionately represented a "cross-section of a lot of our assets," the candidate's son, Donald Trump Jr., said in 2008.Trump's campaign chair and manager, Paul Manafort, spent nearly a decade working for Viktor Yanukovych, the pro-Kremlin leader of Ukraine whose ouster in 2014 led to Russia's invasion of Crimea. His chief Europe adviser, Carter Page, maintains significant investments in Russian oil and gas company Gazprom, which has suffered from US-led sanctions over Ukraine.In an appearance in Moscow earlier this month, Page, at the invitation of Kremlin officials, addressed students on evolving US policy in Europe. Decades-old American foreign policy is driven by an "often-hypocritical focus on democratization, inequality, corruption and regime change," he told the Russian crowd, questioning the authenticity of US democracy itself: "It’s not always as liberal as it may seem."While largely hands off in negotiations over the Republican Party Platform this month, Trump's campaign aides lobbied hard over one issue: Language on Russia over its involvement in Ukraine. And last week, the candidate said he would think twice before coming to the aid of America's NATO allies in the Baltics– which are deeply fearful of a Crimea-style invasion by Russian forces– despite the US' Article 5 commitment to mutual defense.Trump's NATO position amounts to "an open invitation to Vladimir Putin to just roll on in," said Tim Kaine, Clinton's newly minted running mate, in his inaugural campaign speech on Saturday.Russian state-run media has offered the candidate favorable coverage in recent months– Assange himself is now a Russia Today commentator– and Interfax circulated a poll last month claiming that Russians favor Trump three times more often than Clinton."I believe the consensus is that Russia was behind the [DNC] attack," said Danielle Pletka, vice president for foreign and defense policy studies at the American Enterprise Institute. Asked whether she believes Putin is supporting Trump, she replied, "of course.""Intervention? I know the former and suspect the latter," she added.