After more than a decade in power, Russian President Vladimir Putin is struggling through what may be his most turbulent and difficult year in office. His economy is crumbling under the global collapse in oil prices; US and European economic sanctions are punishing his inner circle and most powerful state institutions. His military is still occupying Crimea, and there is little prospect that the shaky cease-fire in eastern Ukraine will produce a long-term solution to the conflict. The murder of opposition politician Boris Nemtsov, just steps from the Kremlin, was a global scandal that embarrassed the regime and prompted massive marches of protest and mourning around the country.

Putin's rule has been secure since he took office in 2000. At some point, though, his problems will become severe enough that the stability of his hold on power will become a live question.

In January, I spoke about Putin's hold on office with Mark Galeotti, a professor at NYU's Center For Global Affairs who has been studying Russian politics for decades. The real question for Putin, he explained, is the loyalty of a few key groups keeping him in power — and what might cause those groups to abandon him. He also explained why he thinks 2016 might be the year Putin's regime finally starts to crumble.

I got in touch with Galeotti again recently to see if his views had changed after Putin's mysterious "disappearance" earlier this month. He told me they hadn't, and gave me his thoughts on what Putin's vanishing act says about the state of politics in Russia. His new comments have been added below. The interview has been edited for length and clarity.

Amanda Taub: You've previously described Putin's power in Russia as "stable but brittle," meaning it's currently strong but would have little resiliency in the face of major economic shocks or other crises. What type of shock would be likely to pose a threat to Putin?

Mark Galeotti: It's always going to be the unexpected shock, so to that extent it's going to be unpredictable.

But let's say there's a bank collapse that can't be bailed out, or something like a health scare. Life tends to throw these kinds of events at all political systems, so it's really about the resilience they've managed to build up. My particular concern would be that they are burning away the political and social and economic capital that gives them that resilience.

AT: How might that kind of crisis cause Putin to lose power? What does the process look like?

MG: It would be a sense among the elites that he was no longer an asset but a danger.

The best parallel would be the ouster of [Soviet Premier Nikita] Khrushchev in the Soviet era [in 1964]. He came to power on the basis of an elite consensus that he could run the country in their interests, but then he became increasingly erratic. He got the Soviet Union involved in the Cuban missile crisis, and made a whole bunch of bad decisions that impacted the Soviet economy.

So the elite decided this guy was not what they were looking for — and he had to go. They basically said to Khrushchev, "You're stepping down for reasons of your health," and there was nothing he could do about it.

2016 is going to be the crunch year

That, I think, is the most likely circumstance for Putin's departure. It's not that he'll lose an election — it's that a bunch of men in gray suits are going to file into his office and say, "Vladimir Vladimirovich, it's time for you to do your last service to the state, and that's to retire."

Or he may be off at his dacha and see on the television that he's just stepped down for reasons of ill health. And he'll pick up his red phone, and find that the people answering it will no longer take orders from him.

AT: Do you think that will be triggered by a specific event?

MG: It's often been the random chances that shape this.

One of the key things that led to Khrushchev's ousting was riots that took place in a town called Novocherkassk. It was a backwater, not at all a significant place. But by bad luck, on the same day they announced an increase in food prices, they also announced a cut in wages at the massive local factory where most people worked. That led to street protests. The police refused to disperse them. And eventually the army was called out, and some of the army officers refused to fire on the protesters. In due course they had to send in security troops, who had no qualms, and there was a massacre.

Nobody heard about Novocherkassk, but the elites knew. And they were thinking, "Novocherkassk was nowhere special. If it could happen there, bad luck could mean it could happen anywhere." When elites feel that pressures are beginning to build up, they will feel they need to act to forestall the random events that could lead to a real crisis.

AT: Is that why Putin's mysterious "disappearance" a few weeks ago prompted such wild speculation?

MG: The circumstances of Putin's recent 10-day disappearance really brought home the extent to which this is a personal regime, whose health and that of the president are inextricably linked.

When Putin vanished we immediately had all kinds of tales to account for it, from coups to births. We still don't know what was going on, although I suspect health issues. We've seen in the past that Putin is very reluctant to let the Russian people know if he is ever anything less than his usual macho self, for reasons of both politics and vanity.

However, the very fact that the West and those Russians in the know were alarmed, and that even the Kremlin apparatus seemed clumsy and unsure of what to do, stress the degree to which if anything happens to Putin the regime will be in trouble — and we do not know what would follow.

AT: Are there any events on the horizon that you think would prompt this kind of crisis?

MG: For me, 2016 is going to be the crunch year.

We're going to see at least a couple of bad economic years. Inflation has just been announced at 11 percent at the end of this year, and it's going to get worse. But it's going to take some time for that to work through the system, for people to notice how much they can't afford anymore. So reason number one is just time.

Reason number two is that in 2016 there are elections for the Russian parliament, the Duma. Clearly the Kremlin is going to massage the results, so the pro-Kremlin parties are all going to do well, there's no question about that. But nonetheless there's the real polling data that the elites will see. And if Putin's numbers are down, that will be a good objective piece of information to say things are going badly.

they've moved from "I believe in Putin implicitly" to "at the moment, Putin's in my interests"

And in 2018 there are presidential elections. If they're going to stand some new candidate, they need at least two years in order to identify a candidate and build a myth around him in order to win the election.

Obviously, who knows what's going to happen? But for all those reasons, if I had to predict a time when I could see all those things aligning, late 2016 is going to be a particularly interesting time in Russian politics.

AT: Are there key constituencies that Putin has already lost?

MG: The cultural elite, mainly. But let's face it, poets do not actually create revolutions.

But I also have noticed a change when I speak to people who I would definitely think of as being in the Putinist wing, such as those who are in the security apparatus or from the military.

A few years back, they were really convinced Putinists. It was an emotional thing. They believed this was a guy who had saved Russia. Now, I think they tend to be pragmatic Putinists. They know that their interests are being served.

But that's the point: they've moved from "I believe in Putin implicitly" to "At the moment, Putin's in my interests."

That's the key constituency Putin has lost: the heart, so to speak.

AT: What is the significance of the pro-democracy movement that has arisen in recent years?

MG: It is important, but not in the sense that it's going to bring Putin down. It's important in the sense that it demonstrates there are people willing to protest, and it provides some sense of an alternative.

It's also important because of the people who are protesting. They are, on the whole, the Muscovite urban middle class, which is a very small fraction of society. But on the other hand, it's disproportionately important in some ways, because these people disproportionately are the kids of bureaucrats and officials, or those kids' fellow students at university.

That's one of the reasons we haven't seen the police be more brutal in their crackdown: who wants to release the riot cops to crack skulls if it might be your next-door neighbor's kid whose skull gets cracked? This is a very small social world we're talking about.

if Navalny reaches out and builds something wider, then that could become dangerous

AT: What about Alexei Navalny? Is he a threat to Putin? (Read here about Navalny and why the opposition leader seems to worry Putin so much.)

MG: So far, Navalny has failed to move out of his comfort zone. When he was riding high in the earlier protest movement, he really did stick to talking to his middle-class Muscovites and his big city constituency. He's much more comfortable pointing things out than building a boring old political machine.

But that's not to say he won't change. If Navalny reaches out and builds something wider, then that could become dangerous.

Beyond anti-corruption, Navalny has one more card he can play, though I wouldn't want to see him play it: street nationalism.

Putin is a nationalist, but it's ultimately a state nationalism, it's about the Russian federation. And Putin deals with non-ethnic Russians all the time, even in his own government. [Russia has substantial numbers of ethnic minorities.] So he can't play the Russian chauvinist nationalist card that much.

But Navalny certainly seems to have demonstrated racist attitudes in the past. And he could play the "we Russians are being bled and exploited by the people from North Caucasus, by the people from Central Asia" card.

That plays to a depressingly powerful strand of common Russian public opinion, and it's something against which Putin has surprisingly little defense. That could conceivably build a wider public constituency quite quickly if Navalny is willing to play that card.

AT: Would that cost Navalny his relationship with the young urban elite?

MG: I think probably not. I don't get the sense that they are necessarily incredibly enlightened in their opinions.

Let's face it: he's the only game in town. So even if there are people within the intellectual classes who were unhappy with a populist shift, it's an open question whether they'd be unhappy enough to say, "That's it." Do you hope that some change, even if it's not ideal, is better than no change at all? I think for many the answer is yes.