The West sees itself as defending Ukraine against Russia, and since it won’t wage military war against Russia it has two main ways to do that, both economic. The first is to shore up Ukraine’s huge economic vulnerabilities, mainly by helping Ukraine pay its bills and plug its deficits. The IMF has pledged $17 billion to that end, the EU a nearly equal sum. The second way the West is defending Ukraine is to levy economic sanctions against Russia to deter it from further aggression.
From Russia’s standpoint, things are more complicated, but in the end there, too, it comes down to economics. Russia sees Ukraine as a front in a war being waged by the West against Russia. Through its actions in Ukraine, Russia is telling the West to stop using the country as a staging ground for operations against Russia. Russia sees sanctions as a yet another weapon in the West’s war. Russia knows it is far inferior to its adversaries in terms of economic size and strength (the combined GDP of Russia’s NATO and EU adversaries is roughly 15 times that of Russia’s), so it has opted not to engage in tit-for-tat responses to Western sanctions. Instead, it resorts to “asymmetric” measures. It looks for weak spots. One obvious such weak spot is Ukraine’s economy. The Russia attitude is, if the Western coalition wants to use Ukraine against us, let them see how much it will cost.