Wow. Our experiment is off to a great start—let's see if we can finish it off sooner than expected.
My view of economic sanctions has been strongly influenced by Dan Drezner, who tells us (if I can oversimplify for the sake of a blog post) that they basically don't work. That's not an ironclad rule, and there are certain situations where they tend to have some effect. However, one of the primary conditions for success is that the sanctions be broadly applied. If it's just one country, they almost never work. The target of the sanctions will simply bear the loss and increase its trade with other partners.
This is especially apropos to our current situation with Russia. Our ability to impose sanctions is limited to begin with thanks to our obligations under the WTO. But that hardly even matters. What really matters is that our trade with Russia is minuscule. Cutting off a piece of our trade would hardly impact them at all. Most of Russia's trade is with Europe and Asia, so no sanctions regime has even a chance of working unless they agree to join in. So far they haven't, and for the obvious reason: they have a lot of trade with Russia. Sanctions would hurt them as much as it would hurt Putin.
The chart below, via Danny Vinik, tells the tale. We simply don't have much trade leverage with Russia. (The export chart looks pretty much the same.) Until Drezner weighs in on this to tell me different, I'd say this is the definitive answer to the question of whether economic sanctions are likely to have any effect on Russia's conduct.