Aiding a Ukrainian insurgency would be painful and costly  

Suppose Russia succeeds in toppling the Ukrainian government or seizing much of the country. Moscow's slow start notwithstanding, this could well happen: The balance of combat power is likely to favour Russian President Vladimir Putin as the war rolls on. So what happens then?

One option being debated in Western policy circles is funnelling arms, money and other support to a Ukrainian insurgency. The strategic case is compelling, but no one should kid themselves about the costs. Waging insurgency would be a frightful business for the Ukrainians doing the fighting, and supporting it would require the U.S. and its allies to brace themselves for escalation.

The Western allies would have several reasons to get behind a Ukrainian resistance. Doing so would help keep the idea of a sovereign, independent Ukraine alive, even after a Russian military victory. A foreign-backed insurgency could also keep Putin's legions bogged down, so they can't quickly pivot to other adventures.

Not least, insurgency can be a powerful tool to impose costs. Sustained resistance could inflict serious casualties on Russian troops, bleed Moscow's economic resources and fuel dissatisfaction with the war at home.

Perhaps an insurgency could eventually make an occupation so unprofitable that Russia undertakes a humiliating withdrawal. Even short of that, it would embroil Putin in a draining, persistent conflict.

The obvious parallel is Afghanistan, another case where poorly motivated Russian occupiers lost to determined defenders. "The Soviet soldier whose father fought heroically at Stalingrad does not have a cause in Afghanistan, but his opponent is fighting a holy war," wrote one U.S. intelligence analyst. A ferocious Afghan insurgency, sustained by foreign arms, training and money, eventually broke the Red Army — and helped finish off a terrible autocratic regime.

But a Ukrainian insurgency wouldn't be a feel-good replay of the film "Charlie Wilson's War." The Afghan war was a nasty affair, which took a heavy human toll on the victors as well as the vanquished. Supporting an insurgency required creating a cross-border sanctuary in Pakistan and then withstanding the Soviet threats — and periodic military raids — that followed.

Moscow, unsurprisingly, didn't take kindly to a concerted effort, sponsored by its foremost enemy, to kill and maim its soldiers. Why would Putin tolerate something similar today?

Consider the practicalities. Weapons and other tangible support would first have to reach Ukraine. That country is progressively losing access to its coastline, so those supplies would have to come overland, from Europe.

This vital land bridge is operational right now, and Western countries are using it to rush in military supplies. If the government falls and an insurgency takes root, Ukrainian fighters would also need bases in Eastern Europe where they can train, equip and recuperate free from Russian military pressure.

But Russia, of course, would have every incentive to disrupt such a sanctuary, because history shows that it would be crucial to the fortunes of the insurgency. Moscow could mount military operations in Western Ukraine to interdict supplies and sever the land bridge. It could even strike insurgent bases and staging points in neighbouring countries.

If Ukrainian insurgents — or sympathetic freedom fighters from other countries — conducted attacks and then fled into Poland, Romania or Slovakia, Putin might feel justified in following them across the border in hot pursuit. Or, perhaps, he might seek counter-leverage against his enemies by stirring up trouble in a vulnerable Baltic state.

Would the protection the North Atlantic Treaty Organisation offers to its members discourage Putin from expanding the war into other countries? Maybe. But it doesn't take a vivid imagination to see how an insurgency in Ukraine could lead to a larger confrontation.

The price of bolstering Ukrainian resistance would thus be a far stronger NATO military posture in Eastern Europe to deter Moscow, as well as explicit guarantees that Washington would support sanctuary states in a crisis. This could create alliance-management challenges: While NATO is united now, it could be a different story if Ukrainian resistance and Russian reprisals created a continual threat of spillover and escalation.

No one should misunderstand what "supporting an insurgency" means. It means encouraging brave men and women to persist in an uphill fight, one in which Ukrainians would suffer terribly in the hope of eventually, perhaps over a period of years, making life miserable enough that a ruthless invader goes home.

It would be a high-stakes contest in resolve, pitting Russia's willingness to crush resistance by any means necessary against Ukrainians' willingness to accept death and repression rather than surrender. The initial romance of resistance would quickly give way to an ugly reality.

The consequences of not making Putin pay exorbitantly for his aggression could be uglier still, which is why Washington and its allies should — and probably will — help Ukraine prevent Russia from consolidating any military victory it achieves. But they shouldn't delude themselves about what this would involve, either for Ukraine or for the West.

Hal Brands. Illustration: TBS

Hal Brands is a Bloomberg Opinion columnist, the Henry Kissinger Distinguished Professor at Johns Hopkins University's School of Advanced International Studies and a scholar at the American Enterprise Institute.

Disclaimer: This article first appeared on Bloomberg and is published by special syndication arrangement.