If you’re the type who finds macho posturing impressive, Vladimir Putin is your kind of guy. Sure enough, many American conservatives seem to have an embarrassing crush on the swaggering strongman. “That is what you call a leader,” enthused Rudy Giuliani, the former New York mayor, after Mr. Putin invaded Ukraine without debate or deliberation.

But Mr. Putin never had the resources to back his swagger. Russia has an economy roughly the same size as Brazil’s. And, as we’re now seeing, it’s highly vulnerable to financial crisis — a vulnerability that has a lot to do with the nature of the Putin regime.

For those who haven’t been keeping track: The ruble has been sliding gradually since August, when Mr. Putin openly committed Russian troops to the conflict in Ukraine. A few weeks ago, however, the slide turned into a plunge. Extreme measures, including a huge rise in interest rates and pressure on private companies to stop holding dollars, have done no more than stabilize the ruble far below its previous level. And all indications are that the Russian economy is heading for a nasty recession.

The proximate cause of Russia’s difficulties is, of course, the global plunge in oil prices, which, in turn, reflects factors — growing production from shale, weakening demand from China and other economies — that have nothing to do with Mr. Putin. And this was bound to inflict serious damage on an economy that, as I said, doesn’t have much besides oil that the rest of the world wants; the sanctions imposed on Russia over the Ukraine conflict have added to the damage.