Russian President Vladimir Putin. (Alexander Zemlianichenko/Pool via AP)
Columnist

What if they had a war and only one side showed up? Russia has been waging war on the West for at least 10 years, and the West hasn’t bothered to notice. This is not, to be sure, a conventional war, with Russian tanks invading Poland or Russian missiles hitting Pittsburgh. Moscow’s kind of war is more subtle and yet all the more effective — precisely because it does not compel an overwhelming response.

The war arguably began in 2008 when Russia invaded Georgia, a pro-Western country that sent troops to Iraq and Afghanistan and was anxious to join NATO. Rather than punishing Vladimir Putin for his aggression, the Obama administration later responded with a “reset” of relations. Putin was emboldened to aggress again: In 2014, his “little green men” — uniformed Russian soldiers with their insignia removed — invaded Ukraine. He annexed Crimea and turned eastern Ukraine into a Russian proxy state. This time the United States and Europe did respond with sanctions — but not strongly enough to dissuade him.

In 2014, a Russian antiaircraft missile shot down a Malaysian airliner over Ukraine, killing 298 people. Instead of apologizing and paying restitution, Putin spread crazy conspiracy theories blaming the shoot-down on Ukraine, the CIA or some other culprit. In 2015, Putin entered the Syrian civil war to help a criminal regime commit war crimes against its own people. Not satisfied with killing Syrians, last month Russian mercenaries attacked a base that held U.S. forces in an apparent attempt to drive the United States out of Syria.

To prevent an effective response from the West, Putin brazenly intervened in the 2016 U.S. presidential election to help defeat Hillary Clinton, a critic, and elect Donald Trump, a fan. He has also meddled in European elections to help pro-Russian candidates. The Russians even fomented an unsuccessful coup to try to prevent Montenegro from joining NATO.

While helping his supporters, Putin has not hesitated to eliminate his critics, both at home and abroad. BuzzFeed reported last year that Putin may have killed 14 people in Britain and at least one in the United States. In 2006, according to a British inquiry, two Russian agents murdered former Russian intelligence officer Alexander Litvinenko by spiking his tea with radioactive polonium-210. Last week, another Russian turncoat, Sergei Skripal, and his daughter, Yulia, were poisoned in Britain with another exotic weapon — a Russian nerve agent known as Novichok. That Putin is taking so little care to conceal his “wet work” suggests that he wants to send a message: This is what happens when you cross me.

Putin has little reason to fear retribution because he has suffered so little to date. After Russia’s assault on U.S. democracy, President Barack Obama expelled 35 Russian diplomats. Putin responded by eliminating more than 750 positions at U.S. diplomatic outposts in Russia. Now British Prime Minister ­Theresa May has expelled 23 Russian diplomats. Putin will retaliate in kind. But he couldn’t care less. What might get his attention is an overwhelming response led by the United States.

The Trump administration has now joined Britain, France and Germany in decrying the “first offensive use of a nerve agent” in Europe since World War II, while the Treasury Department has sanctioned the Russian hackers accused by special counsel Robert S. Mueller III of having taken part in the subversion of the 2016 U.S. election and other cyberattacks. It’s a start, but not much more than that.

President Trump still has not personally called out Putin in the way he has assailed everyone from Alec Baldwin to New York Times reporter Maggie ­Haberman. Trump has begrudgingly allowed the sale of weapons to Ukraine but won’t enforce the sanctions passed by Congress. In 2012, Congress enacted the Magnitsky Act to sanction Russians involved in human rights abuses. Obama sanctioned 44 individuals under the law; Trump only five.

Trump’s unwillingness to criticize ­Putin makes you wonder what hold the Kremlin has over him; the Steele dossier looks more credible all the time. But no one is alleging that May has been compromised, and her actions are just as pusillanimous.

What would the West do if it were to get serious about Russian aggression? Putin and his cronies have billions of dollars stashed in the West. London is a particular favorite of Russian exiles. Freeze the money. Seize the properties. Hurt them where it counts. The United States can also designate Russia a state sponsor of terrorism, just like North Korea, which also used a nerve agent for an assassination abroad. Stop treating Russia like a legitimate state: Putin has already been kicked out of the Group of 8 gatherings; he can be removed from the G-20, too. Kick Russia out of the SWIFT system, denying Russian banks access to international monetary transfers. Invoke NATO’s Article 5 collective-defense clause.

There is a rich menu of retaliatory options — none of which would risk a nuclear war in spite of Putin’s saber- ­rattling. Empty words aren’t enough. Stronger action is needed to make the Russian strongman realize he can’t win this undeclared war without a fight.