How they did it (and will likely try again): GRU hackers vs. US elections

In a recent press briefing, Deputy Attorney General Rod Rosenstein announced that the grand jury assembled by Special Counsel Robert Mueller had returned an indictment against 12 officers of Russia's Main Intelligence Directorate of the Russian General Staff (better known as Glavnoye razvedyvatel'noye upravleniye, or GRU). The indictment was for conducting "active cyber operations with the intent of interfering in the 2016 presidential election." The filing spells out the Justice Department's first official, public accounting of the most high-profile information operations against the US presidential election to date. It provides details down to the names of those alleged to be behind the intrusions into the networks of the Democratic National Committee and the Democratic Congressional Campaign Committee, the theft of emails of members of former Secretary of State Hillary Clinton's presidential campaign team, and various efforts to steal voter data and undermine faith in voting systems across multiple states in the run-up to the 2016 election.

Reading between the lines, the indictment reveals that the Mueller team and other US investigators likely gained access to things like Twitter direct messages and hosting company business records and logs, and they obtained or directly monitored email messages associated with the GRU (and possibly WikiLeaks). 

After digging into this latest indictment, the evidence suggests President Trump may not have made a very good call [on the matter of whether Russia was involved in the hacking]. But his blaming of the victims of the attacks for failing to have good enough security, while misguided, does strike on a certain truth: the Clinton campaign, the DNC, and DCC were poorly prepared for this sort of attack, failed to learn lessons from history, and ignored advice from some very knowledgeable third parties they enlisted for help.