Two weeks into its war in Ukraine, Russia has achieved less and struggled more than anticipated at the outset of the biggest land conflict in Europe since World War II. But the invading force of more than 150,000 troops retains large and possibly decisive advantages in firepower as they bear down on key cities. Moscow’s main objective — toppling the Kyiv government and replacing it with Kremlin-friendly leadership — remains elusive, and its overall offensive has been slowed by an array of failings, including a lack of coordination between air and ground forces and an inability to fully dominate Ukraine’s skies. Two weeks of war have created a humanitarian crisis in Ukraine that has accelerated in recent days. The United Nations estimates that 2 million Ukrainians have fled their country, and the number is expected to grow. Russia likely has had between 2,000 and 4,000 troops killed thus far. With no sign of Russian President Vladimir Putin backing away, the war appears likely to drag on.