BERLIN — In 2015, suspected Russian hackers broke into the computer networks of the German Parliament and made off with a mother lode of data — 16 gigabytes, enough to account for a million or more emails.
Ever since, German politicians have been watching nervously for the fruits of that hack to be revealed, and for possible embarrassment and scandal to follow. Many warily eyed September 2017 — the date of the next German election — as the likely window for Russian meddling to once again rattle the foundations of a Western democracy.
But with the vote only two weeks away — and with Russian President Vladimir Putin's European nemesis, Chancellor Angela Merkel, seemingly on track for a comfortable win — the hacked emails haven't materialized.
Nor have Russian-linked propaganda networks churned into overdrive with disinformation campaigns. Even Kremlin-orchestrated bots — blamed for the viral spread of fake news in last year's U.S. presidential campaign — have been conspicuously silent.
The apparent absence of a robust Russian campaign to sabotage the German vote has become a mystery among officials and experts who had warned of a likely onslaught.
Have Germany's defensive measures — significantly boosted after the hacks and propaganda campaigns that preceded last November's U.S. vote — actually succeeded? Or has Russia decided to pull back, reckoning that the costs of antagonizing Merkel outweigh the benefits?
Or perhaps Moscow is simply biding its time.
"That's what makes me worried," said Maksymilian Czuperski, director of the Atlantic Council's Digital Forensic Research Lab. "Why is it so quiet? It doesn't feel right."
Much is at stake for Russia in the German vote. Merkel, a Russian speaker who has jousted with Putin throughout her 12-year tenure as chancellor, is critical to the Western alliance's chances of hanging together amid a concerted Russian campaign to pick it apart.
To her left and her right are German parties that have advocated a far softer line on Moscow. The far-right Alternative for Germany (AfD) party, in particular, has taken stands that would please Putin, including calls to abolish the European Union.
Putin has denied that his government is behind efforts to influence elections in the United States and beyond, while coyly acknowledging that "patriotically minded" Russians may be acting on their own.
But if Russia was hoping to undermine Merkel before the Sept. 24 vote, it doesn't appear to be working: Her center-right party has remained well ahead of all competitors in all polls, while the AfD's support seems to have topped out at about 10 percent.
Whether Russia makes a concerted push to meddle may not be known until election night — or beyond. German authorities are certainly not yet declaring victory, and they have urged politicians and the public to remain on alert as the campaign hits the homestretch.
In recent days, German cybersecurity officials have warned that Russian-linked networks may try to manipulate the vote count, perhaps throwing the outcome into disarray. And the country's top domestic intelligence officer said his staff is conducting hourly checks of sites such as BTleaks to make sure there's no fresh sign of the hacked documents from the Bundestag, the German Parliament.
Meanwhile, a leading Merkel ally reported that on the eve of the campaign's only nationally televised debate this month, her website was hit with thousands of cyberattacks — many of which appeared to emanate from Russian IP addresses.
But overall, officials and experts say the scale of apparent Russian interference is far lower than they had expected.
Volker Wagner, chairman of the German Association for Security in Industry and Commerce, said his group recently conducted a comprehensive survey of its members on the issue and came up empty.
The organization, which works closely with German intelligence agencies to counteract shared threats, did not find "any evidence . . . that there are more sophisticated attacks coming from Russia in the pre-election period."
Czuperski, meanwhile, said the stream of fake news and bot-spread disinformation had visibly slowed.
If evidence of Russian meddling continues to be minimal, experts say, there may be valuable lessons in understanding why Germany has proved unusually resilient.
One is that German authorities have been especially aggressive in trying to publicize and combat Russian sabotage efforts as they emerge — a contrast to the United States, where the Obama administration last year was reluctant to sound the alarm on what intelligence agencies later concluded was a concerted Russian campaign to help then-candidate Donald Trump defeat Hillary Clinton.
When pro-Russian news outlets began circulating a story last year about a Russian-German girl named Lisa who was allegedly abducted and raped by Arab migrants, German officials shot down the story and accused Moscow of "political propaganda."
German intelligence officials have also named Russian-linked groups as the likely culprit behind the Bundestag hack, and they have been outspoken in their belief that Moscow will try to sway the German electorate against Merkel.
German lawmakers, meanwhile, in June passed stringent legislation that imposes multimillion-euro fines on companies that fail to remove fake news and defamatory content from their websites.
The legislation, which was vigorously opposed by Facebook and other social media firms, does not go into effect until October. But already, companies have begun to comply.
Patrick Sensburg, a Merkel ally in Parliament and an intelligence expert, said he has reported some 30 accounts to Facebook in the past several months that he suspects of being pro-Russian bots. The accounts all have the same friends, offer no personal details and use the same language to attack him.
"They'll say, 'Are you a Muslim?' or 'Merkel let everybody in' or 'You're selling out our country,' " he said.
In most cases, he said, Facebook has acted on his complaints by taking the accounts down.
"We're in the beginning on social media of the fight against fake news and fake accounts," he said.
German defense may not account entirely for the apparent lack of a game-changing Russian offense.
Sijbren de Jong, a Russia expert at the Hague Center for Strategic Studies, said the Russians may have decided to play a less aggressive role in the German vote after they "overplayed their hand in the U.S."
For a variety of reasons, de Jong said, direct interference in German elections would be a risky bet. Not least are the economic considerations for two countries that remain close trading partners, despite sanctions that Merkel has championed.
"The German economy is a large market for key Russian companies," he said. "You don't bite the hand that feeds you."
Nor do you meddle in a vote where the outcome appears preordained. Several German parties — including the far-right AfD, the center-left Social Democrats and the far-left Die Linke, or the Left — have far more Moscow-friendly policies than the ones espoused by Merkel's Christian Democrats.
But even after 12 years of Merkel, German voters appear in little mood to shake up the system and veer away from her studied centrism.
"The intention [of Russia] is to destabilize European society," said Annegret Bendiek, an analyst with the German Institute for International and Security Affairs. "In Germany, that's not so easy."
Bendiek said it is still possible that in the waning days of the campaign, Russian operatives will try to unsettle things. But she's doubtful. Even the hacked Bundestag documents may never see the light of day, if only because the people who stole them may have concluded that they wouldn't change anything if they did.
Hacking into the inner sanctum of German politics was one thing. But finding anything salacious or tawdry among what are likely to be hundreds of thousands of tedious policy documents, Bendiek said, is quite another.
"It's been my job for 10 years to read these kinds of documents," she said. "You can't imagine. They are so boring."
Luisa Beck contributed to this report.