Similar campaigns involving hacks, violent rallies and dark conspiracy theories have worked in other countries, including Georgia, Poland and Ukraine. Risky on the face of it, the US operation did no harm to Russia's interests. On the contrary, the pro-Russian candidate won; business looks set to continue as usual.
2 We know that the Russian operation has already begun.
Last week, the head of the German domestic intelligence agency said that material hacked from the German Parliament, published recently by WikiLeaks, came from the same Russian group that stole material from the Democratic National Committee.
He believes "increased cyber spying and cyber operations" are underway. The head of Germany's foreign intelligence service has identified a rise in cyberattacks designed not to steal defence or commercial information but rather "to elicit political uncertainty".
Not that hacking is the only tactic. Earlier this year, Russian media and pro-Russian trolls helped to create online hysteria by promoting a fake story of a Russian girl allegedy raped by a Syrian immigrant. Russia has also offered financial and moral support to Germany's far-right and far-left parties, just as it does in France, Italy and elsewhere in Europe.
3 We know what the operation's goals will be.
There may well be a specific goal: defeat Chancellor Angela Merkel, who responded to Russia's annexation of Crimea with support for sanctions that are particularly hurtful to Russian President Vladimir Putin's inner circle.
But there are certainly some broader goals: discredit democracy, in order to prevent Russians from agitating for it at home; undermine the European Union, in order to make the continent more amenable to corruption and authoritarianism; and demoralise Nato, which is preventing Russia from flexing its military muscles in its periphery.
4 We know that huge resources have been invested already.
In the past decade, Russia has funnelled many millions of dollars into its public propaganda arms, the television channel RT and the website Sputnik, which now exist in multiple languages, including German.
Less visibly, Russia has invested an equivalent sum in friends: think-tanks, businessmen, even politicians. Matthias Warnig, an ex-Stasi officer who knew Putin in his KGB days, is managing director of Nord Stream AG, the company that operates the gas pipeline that links Germany and Russia beneath the Baltic Sea. Gerhard Schroeder, the former German Chancellor, is now the chairman of the shareholders' committee of that same company.
5 We also know - or should know - why they could succeed.
Long before anyone else, the Russian Government spotted deep flaws in Western democracy. It realised that Western politicians could be bribed; that offshoring worked in oligarchs' favour; that anti-corruption laws weren't well enforced; that Western media was weak; and that social media had undermined trust in traditional sources of authority. Russian leaders also understood that, thanks to the global reach of the Internet, disinformation was far easier to produce and promote than ever before.
Merkel has also made serious mistakes. However well meant, her unilateral offer to house Syrian refugees in 2015 gave millions across the continent the impression that Europe no longer controls its borders. Terrorist attacks increased this anxiety. Germany has failed to back European solutions to crises in the Middle East, failed to take seriously the need for European defence, failed to invest in Nato. The bill for all of those failures is now coming due.
In the coming months, Russian media, and Russian-backed parties in Germany, will have no compunction about running openly an anti-immigrant, anti-American, anti-EU electoral campaign.
They may have an unexpected ally: Breitbart, the far-right website run until recently by Stephen Bannon, incoming White House chief strategist, has announced it will invest in a German-language website, too.
As a state, and as a democracy, Germany has huge advantages.
Economic success means that Germans still trust their government more than many other Europeans. The relative strength of German media means that the horrible insult, lugenpresse - lying press - once used by the Nazis to smear mainstream media and now used by the far-left and far-right for the same purpose, doesn't affect everyone.
German security officials say they already meet regularly with senior journalists, briefing them on stories they think are fake.
Merkel and other German politicians have spoken openly of the threat.
But is the anticipation of a disinformation campaign enough to rob it of its power? We are about to find out.
