Putin strikes again. Prepare for more.

Vladimir Putin, the former KGB agent, like the Russian bear who roams the Siberian wilderness, has once again, pawed his neighbor, the independent nation of Ukraine. That should not have surprised us.

From the very beginning of his two-decade reign, Putin has declared that the Soviet Union’s collapse was the greatest geopolitical catastrophe of the 20th Century. He wants the former lands of the Russian Empire back, including the most prized package of all, Ukraine. To this end, on Monday he formalized his 2014 grab of parts of Ukraine, Luhansk and Donetsk and sent in Russian troops. He may invade further and continue to attempt to destabilize Ukraine, Eastern Europe and the U.S. It’s part of his game plan.

Russia must be stopped.

First, we must ratchet up severe economic sanctions, so strong that it will bring the Kremlin to its knees. We have made a good start. A fine first step is that Germany has agreed to halt certification of the gas pipeline from Russia. Granted, Putin may have discounted sanctions. Like all despots, he doesn’t worry about the condition of his people. Strong economic measures, however, will weaken his flagging economy.

Secondly, we must arm Ukraine to the hilt and politically support its citizens. Given the wherewithal, they will fight. No one is calling for U.S. troops to be sent to Ukraine. But we can show the Ukrainians, ‘we’re with you.’ By doing this, we deter other dictators from similar illegal actions.

Third, we must get our message to the Russian people through measured information that Putin’s rash action is bringing the world to the brink of war. In my several past travels throughout Russia, I never heard anything but hopes for peace from Russian men and women.

Americans have to show the world that, despite our internal differences, we are united when our security is threatened. In the 21st century, Ukraine is as close as Canada. We can’t wish this crisis away. Applying sanctions and other measures will undoubtedly bring reprisals from Moscow. Higher gas prices, cyber-attacks and more. But we can’t be complacent. No room for appeasement.

Putin may be a skilled chess player. We must be better. We can’t allow him to say, “checkmate.”

Ben G. Frank, a resident of Boynton Beach, is a journalist, lecturer and author of books on Russia and Ukraine, including the just-published, historical novel. “Klara’s Brother & The Woman He Loved.”

This article originally appeared on Palm Beach Post: Opinion: Putin must be stopped.