Can Ukraine keep winning?

The newly focused battlefield has other tactical advantages for Russia, too:

It can concentrate its troops in Donbas, and a direct conflict between the countries’ armies seems to favor Russia. When the war began, it had more than twice as many troops as Ukraine, according to the International Institute for Strategic Studies.

The Donbas region borders Russia, allowing Putin’s generals to build shorter and less exposed supply lines than they needed elsewhere in Ukraine.

Russia is familiar with the territory. It began fighting sporadic battles in Donbas in 2014 and has since been supporting separatist rebels there. The new head of the war effort, General Aleksandr Dvornikov, has overseen Russian operations in Donbas since 2016, after commanding Russian troops in Syria.