Vladimir Putin is faced with a Russian economy going nowhere because of mild Western economic sanctions, and with the prospect of much harsher sanctions if he pursues efforts to destabilize and carve up Ukraine. So the Russian president now appears to be abandoning his Ukrainian supporters to their fate. Already those separatists are paying a price for his meddling.

In a very welcome development, Ukraine's military has pulled itself together and is gradually retaking cities seized by pro-Russian Ukrainian rebels formerly led by covert Russian officers, but now lacking Russia's help. The fighting is in areas bordered by Russia and largely populated by Russian-speaking inhabitants. Those areas are separate from Crimea, where Russian control is unchallenged.

The rebels have withdrawn to a couple of cities, Luhansk and, principally, Donetsk, where they have destroyed bridges and are preparing for urban combat. But they appear to be looking in vain for continued support from Russia.

The Wall Street Journal reports one rebel leader complained that the lack of a Russian intervention "means it will be a long and bloody war until we all die valiantly on the barricades."

However, a Russian diplomat predicts that the fighting will be over in a few weeks. But reconciliation in the war-torn areas, he added, "will take years." That comment suggests that Mr. Putin does not plan to bring pressure on the rebels to reach a political accommodation with the Ukraine government but prefers that they become martyrs to a lost cause that will keep alive separatist sentiment for generations and weaken Ukraine.

If so, it would represent the height of cynicism. Mr. Putin and his propagandists did all they could to fan the flames of separatism by denouncing the Ukrainian government as illegitimate and "neo-Nazi," and by supplying weapons and leaders to the armed rebellion. Now Mr. Putin recognizes the Ukrainian government.

The turn away from the separatists also exposes a weakness that could bedevil the Russian leader, whose popularity with Russian voters leapt upward when he seized Crimea. Putin's dilemma is that if he pushes onward in support of pro-Russian Ukrainians the Russian economy could well take a very hard hit from which it could take years to recover. The International Monetary Fund, in a report issued last week, said future economic growth in Russia depends heavily on investment capital coming to Russia instead of fleeing it, as it has over the past five months.

On the other hand, leaving pro-Russian separatists in Ukraine to their fate could turn nationalistic Russians against Mr. Putin, weakening his hand in carrying out essential economic reforms without which Russia will continue to struggle and fail to attract investment.

Meanwhile, Ukraine has signed an economic pact with the European Union that Mr. Putin spent years trying to block. Things are finally looking up for Ukraine.

But not for Mr. Putin.