Of great interest is the insight as to the aims:
Putin's objectives were multifaceted, a high-level intelligence source told NBC News. What began as a "vendetta" against Hillary Clinton morphed into an effort to show corruption in American politics and to "split off key American allies by creating the image that [other countries] couldn't depend on the U.S. to be a credible global leader anymore," the official said.Great powers don't do vendettas, but they do punish their enemies in ways that are useful to them. The DNC hack was useful to Putin at home because it defused the force of the Clinton charges against his own electoral system (which he will face again, to whatever degree of peril, in 2018). Showing that Clinton was herself the leader of a deeply manipulative, indeed rigged, primary system would make the presumptive President Clinton less powerful as a Russian critic.
So, in addition to her devotion to a "No Fly Zone" in Syria -- which we've discussed repeatedly -- here was an important enough interest to make this worth doing. If the leaks did nothing else, Putin could point to US media outlets' coverage of the DNC corruption as a defense against American criticism of his re-election campaign.
What is of importance here is that the leaks were anti-Clinton, rather than pro-Trump. Since the leaks began around the time of the DNC, when both primaries were decided, it is easy to become confused about that: the race was binary at that point. But the campaign seems to have been targeted at Clinton and at doing damage to what the Russians probably assumed (like everyone else) would be the incoming administration.
Further evidence along this line comes from a Newsweek report from before the election. The author is sure the Russians are 'favoring Trump,' rather than 'opposing Clinton,' but look at this:
By August, however, fears began to emerge within the Kremlin that the effort was falling apart. Trump’s attacks on the parents of a slain Muslim American soldier following the father’s speech at the Democratic convention created dismay in the Kremlin. Top Russian officials came to believe Trump would be forced to withdraw from the race because of his psychological state and apparent unsuitability for the presidency, according to information obtained by the Western intelligence source. In particular, Kremlin officials feared they could not predict what impact it might have on Russia should Trump step aside. As a result, the Russians decided to stop forwarding material through channels to WikiLeaks...I've cut out a bit in the middle about an alleged Russian attempt to buy one of Trump's advisers, Manafort, who was forced to resign from the Trump campaign over the charges. The truth of the charges is contested, but the Russians wouldn't be trying to buy something they already owned -- and they wouldn't bother buying the adviser if they owned the candidate.
By October, “buyer’s remorse” had set in at the Kremlin, according to a report obtained by Western counterintelligence. Russia came to see Trump as too unpredictable and feared that, should he win, the Kremlin would not be able to rely on him or even anticipate his actions.
So it looks like Putin started off with the hope of damaging Clinton's credibility as President, and securing his own position. If he could beat her, he had a great deal more to gain in Syria.
However, Trump is just as much a roll-of-the-dice for the Russians as he is for us. He's his own man, for good or ill, and nobody's sure just what he might do. I'm not sure how much of a comfort that is, but it is at least not 'politics as usual' from here on.
UPDATE: An excellent discussion called, "When does a President become a National Security risk?" featuring John McLaughlin. It's a fair-minded look at the whole set of questions.