UKRAINE FACES THE PURSUER’S DILEMMA: The choice between “keeping up the skeer” and avoiding over-extension and a dangerous counterattack:

On Monday, the Ukrainian military claimed to have advanced over the past day into an additional 20 Ukrainian towns and villages in the Kharkiv region that had been under Russian control, adding to the hundreds of square miles it has retaken in the northeast. It also said it had recaptured nearly 200 square miles in the southern Kherson region in recent days, as its forces try to cut off thousands of Russian forces stationed west of the Dnipro River.

The military’s assertions could not be independently verified, but Western analysts, including at the Pentagon, said that the Ukrainians were overall making gains as quickly as Russian forces were falling back.

But Ukraine faces potentially serious pitfalls if it pushes any farther.

Any future advances would mean that Ukrainian forces would further extend their supply lines, straining convoys of fuel, ammunition and reinforcements as they have to move farther away from their established logistics hubs.

That could leave Ukrainian units vulnerable, said John Blaxland, a professor of security and intelligence studies at the Australian National University in Canberra. Although he added that a Russian counterattack was “not necessarily going to happen,” in part because the morale of Moscow’s troops appears to be foundering.

Russian officials face their own hard questions, especially with a growing backlash to their “special military operation” from pro-war voices at home. Russia’s military leaders, analysts say, will have to take a cleareyed look at the reality of their forces’ current conditions — depleted and demoralized in some areas — to determine how much of Moscow’s goals they can accomplish in the coming months, if any.

They will also have to contend with the rigid structure of Russia’s military and, ultimately, the decisions of Mr. Putin, who has resisted mobilizing a national draft and sought to preserve a sense of normalcy inside Russia.

That’s going to be hard to keep up.