[icarus]

Ukrainians motivation is different. They already have been drafted to fight and the destruction and killing of their fellow citizens motivated them.

Russians on the other hand used their professional army.
Most families this war us a distant event a special ops that does not affect them directly. But once their own sons are drafted to fight and start dying its a different story.

Lets not assume that all Ukrainians are equally motivated behind Zelensky in insisting to fight on instead of negotiating for peace, just as not all Russians are behind Putin in the military operations. 

One third of military age men fled Ukraine and bribed their way out of the country, at the start of the conflict. Those left behind are men who cannot run, too old to run, too poor to run. And so when forced to the frontlines, they abandon positions or be killed. 

The media censorship in Ukraine and banning of political opposition prevent Ukrainians from seeing the true losses in the frontlines. And the Ukrainian Security Branch ensure that dissent within the population is dealt with. 

Russia has not declared war in Ukraine, without which, there can be no national draft. That's a political decision only Russians can make, if the Ukrainians stupidly made them do it.