Thomas Wonder has a great piece in War on the Rocks on the effects of Western sanctions against Russia:
At a broad level, Russia has not modified its behavior since the initial imposition of sanctions in 2014 over the annexation of Crimea. Since then, Russia has rescued President Bashar al-Assad through a brutal air campaign, conducted disinformation campaigns targeting U.S. and European elections, and tried to kill a defector on British soil with a nerve agent, all the while continuing its actions in Ukraine that provoked the original sanctions — including the detention of three Ukrainian navy ships in the Kerch Straits on Nov. 25. Domestically, Putin and his supporting cast of loyalists have largely cruised to election victories at all levels of government despite a slow-growing economy and unpopular social reforms.
That’s not how sanctions work. No one changes behavior because of economic sanctions, but that doesn’t mean that the tool is broken or should be avoided.
Sanctions are a good way to show disapproval. If the other options are to do nothing or to wage war, sanctions are by far the best alternative. No one expects them to work in the short term, because they are introduced at a time when the “target country” is heavily invested in whatever behavior the sanctions are about. A normal state can be deterred by the threat of economic punishment the same way that a normal citizen can be deterred by the threat of a speeding ticket. But once you take the step to shoot your way out, you are beyond the point where a fine will stop you.
However, while sanctions don’t work as a tool of punishment, they are a pretty good tool of reward. Some day, another Russian leader than Putin will be in a position where lifting sanctions becomes a priority.