Third, while there is no question that sanctions have inflicted real costs on the leading state-owned and state-affiliated companies and harmed Mr. Putin’s cronies, the collateral damage to independent, private enterprise in Russia is incomparably worse. Businesses without political protection will see atrophied sales, no access to finance and an indefinite postponement of investment. Those enterprises that put the greatest store on Russia’s integration with the European Union and the United States are being hit hardest. (One of us is an American investor and entrepreneur who has long been active in Russia and is witnessing this first-hand.)

The most daring Westernizers among Russia’s small entrepreneurial class now find themselves without protection while state banks and energy companies continue to be shielded by their access to government credit obtained on favorable terms.

Fourth, by imposing sanctions on Russia when it was already falling into a downward economic spiral, Washington has given Mr. Putin a powerful political instrument to deflect blame for the consequences of his own baleful decisions in Ukraine. The Kremlin’s model of “state capitalism” was already struggling and its performance would have been poor without the geopolitical upheaval that Mr. Putin has created. American sanctions arrived with perfect timing, providing him an alibi that he has skillfully used to confuse the Russian people about the cause of their economic woes.

Fifth, even if sanctions are carefully crafted to punish specific actors, ordinary Russians perceive the West’s sanctions to be directed against them and it is they who are being forced to bear the real costs of soaring inflation, the ruble’s collapse and slowing growth. Russians’ sense that they are under attack has generated an understandable “rallying around the flag” phenomenon. Mr. Putin’s all-time-high approval ratings are one result; the other is the near-complete marginalization of dissenting voices. Sadly, Sunday’s march to memorialize the slain opposition leader, Boris Nemtsov, will not change this.

If Russia faces greater economic turbulence in the coming months and years, America could face far more intractable problems than those that exist today. Russia is likely to become more belligerent if externally inflicted economic blows deepen the country’s crisis. Moreover, a deeper downturn in Russia would worsen the economic woes of the European Union, with potential knock-on effects globally.