We just got a glimpse of how oligarch-funded militias could bring chaos to Ukraine

It's never good news for the rule of law when an oligarch sends armed men in combat fatigues to occupy a state-owned oil company. That's what just happened in Ukraine, where billionaire oligarch Igor Kolomoisky appears to have sent members of his private army last week to temporarily take over the offices of oil company UkrTransNafta in order to protect his financial interests in the company.

The situation may be even more frightening than it sounds.

Kolomoisky funds and directs a large private militia that has been helping the Kiev government fight against the pro-Russian separatists in eastern Ukraine. Militias like his — and there are dozens of them — are a source of deep concern to analysts who believe they could threaten Ukraine's long-term stability.

Are these private armies willing to follow Kiev's orders without question? Or will they go their own way when their own interests are at stake? Kolomoisky's antics at the oil company's offices, in which he appears to have used his private army to protect his personal financial interests, look an awful lot like the latter.

Kolomoisky, an oligarch who is also the governor of Ukraine's Dnipropetrovsk region, is a significant backer of the pro-Kiev private militias fighting in the country's east. He funds the Dnipro Battalion, a private army that, according to the Wall Street Journal, has 2,000 battle-ready fighters and another 20,000 in reserve. Newsweek reported that Kolomoisky has funded other militia groups, as well.

The conflict has empowered pro-Ukraine militias like Kolomoisky's because the Ukrainian military was too weak to fight the separatist insurgency on its own. When Russia annexed Crimea in early 2014, Ukraine had only about 6,000 combat-ready troops. The paramilitary "volunteers" bolstered the fighting forces, funded in part by private donations from wealthy oligarchs. Bands of politically motivated thugs, dating back to before the conflict, grew into more substantial militarized battalions. There are now an estimated 30 "volunteer" militias fighting the separatists in eastern Ukraine.

Kolomoisky's fighters may have helped keep his region out of the hands of the pro-Russian separatists. But in the long run, it could pose a threat to Ukraine's stability.

Ukraine's oligarchs have a long history of resisting the state. The fact that Kolomoisky has now raised his own militia raises the deeply alarming possibility that he — and others like him — could regularly use these fighters to protect his interests from state interference.

The worrying thing about Kolomoisky's raid on the oil company last week is that it seems to have partially worked: Kolomoisky may not have been able to keep his ally in the chairman's job, but he reportedly said that he and Ukraine's president have reached an agreement to install a temporary chairman for UkrTransNafta who "would not be carrying out any investigations of its finances." Kolomoisky has significant interests in the oil company; now, it seems, he's been able to use his private army to shield his business dealings from legal or financial scrutiny.

While fighting the war against the separatists might be a priority now, at some point the Ukrainian government needs to be able to govern Ukraine. It can't do that if parts of the country are dominated by militias that don't obey any official authority.

Adrian Karatnycky, a senior fellow at the Atlantic Council, warned during an interview in February that simply by existing, those private armies could be "creating enough of an implicit threat that the government can't move against, say, corrupt schemes." The events in Ukraine last week suggest his concerns were well-placed.

These groups pose a serious threat to Ukrainian civilians, as well. In December, pro-Kiev militias blocked humanitarian aid from reaching rebel-held areas of eastern Ukraine. Amnesty International researcher Denis Krivosheev said the militias were using starvation of civilians as a weapon, and called the tactic a war crime.

Another militia, the Aydar Battalion, has kidnapped and tortured civilians on dozens of occasions, according to Amnesty. Local police told the human rights group they had registered more than 38 criminal cases against Aydar members but lacked the power to take any further action against the fighters — a worrying sign of the militias' power.

As time goes on, the things that made the militias useful for Ukraine will also make them dangerous. Their strength and autonomy in eastern Ukraine, particularly compared with the relatively weak government, could potentially give them tremendous power there. These are the conditions for warlordism — for militias turning their pieces of territory into little fiefdoms that they or their wealthy patrons would be free to govern, or exploit, as they wished.

The experts I spoke to agreed that the militias represent a threat to the long-term stability of Ukraine, and ought to be dissolved and incorporated into the regular security forces. But it's not clear whether President Petro Poroshenko's government sees that as a priority — or whether the government is equipped to take them on at all.

Karatnycky, of the Atlantic Council, said the militias had served an important purpose but that it was time for Ukraine to move to a purely professional military. The Brookings Institution's Steven Pifer agreed, saying that any increase in US military assistance to Ukraine should be tied to a commitment to dissolve the volunteer battalions.

Pifer said he is certain Poroshenko would agree, if pressed, that professionalizing the fighting forces is a good idea. But the president may be too focused on winning the conflict now, or on implementing other types of reforms, to take a step that is difficult but in his long-term interests.

It's also not clear that Poroshenko has the political capital to take on the militias anyway — his own interior minister has close ties to one such private army, the Azov Battalion, so would be unlikely to support any policy that would undermine it.

One more crucial unknown factor is whether oligarchs like Kolomoisky would be willing to give up their ties to militias and the power they bring — and how they might respond if the Ukrainian government moved to disperse their groups.

The militias themselves might not go quietly, either. In early February, when Poroshenko was rumored to be considering disbanding the Aydar Battalion, the group marched on Kiev. Its fighters blocked access to the ministry of defense and burned tires outside its gates until Poroshenko backed down. In September 2014, the Guardian's Shaun Walker embedded with the Azov Battalion in Mariupol and found "almost all to be intent on 'bringing the fight to Kiev' when the war in the east is over."

If they get their wish, it could be yet another disaster for a country that recently seems to have had little else.