The word from Andrey Illarionov, a former economic advisor to President Putin and now senior fellow at the Center for Security Policy in Washington, is that Russia’s invasion of Ukraine “does not seem like everything is going according to Putin’s plan.” 

“It could be a very bloody and fierce and very long war,” Mr. Illarionov, who is famed for his free-market economic views, warned in an interview with The New York Sun. He said that the Ukrainians “are ready to fight and they are not going to give up.”

Mr. Illarionov urged Americans and Europeans to take immediate action. He called the early sanctions a “joke” and warned that Mr. Putin is “very satisfied” with that outcome. To make a difference, he said, “the United States needs to impose an embargo on oil and gas exports from Russia right now.”

The ex-aide to Mr. Putin made his comments Thursday, before the Biden administration announced that direct sanctions were being put on the Russian president. “Direct military support would also make a difference,” Mr. Illarionov told the Sun, as would “opening a criminal case in The Hague against Mr Putin.”

“Those things,” he said, “would at least stop the war.”

“Americans need to demand that its government send military arms and all possible equipment to Ukraine and that it mobilize Europe to do the same.” That means “military aid, transport, medical equipment, and a call for all volunteers who want to fight for Ukraine to do so.”

Asked what Mr. Putin’s goal is, Mr. Illarionov responded: “To destroy Ukraine.” The Russian leader’s “clearly announced goal is to force President Zelensky to capitulate.” 

If Mr. Zelensky does so, he warns, Mr. Putin “will move next to Baltic countries.” Mr. Putin and his allies “are very creative in producing many scenarios” with which to attack these countries, he added. 

Asked what President Biden doesn’t understand about Mr. Putin, Mr. Illarionov retorted: “Mr. Biden understands Putin very well. It’s a joint game. Biden promised Putin he would put pressure on Zelensky to accept Minsk II.”

Minsk II refers to a February 2015 agreement that ended the fighting that began in 2014, when Mr. Putin sent forces into Ukraine. The agreement has been problematic for Ukraine, particularly, as one Ukrainian expert, Adrian Prokip, has written, in “providing a special constitutional regime for the Donbas (with requisite amending of Ukraine’s constitution).”

The Minsk Agreements paved the way for “Russia-backed separatists in the Donbas [to] become a political force in Ukraine, quite likely under the control of the Kremlin, with the chance of gaining representation in parliament and, eventually, executive power.”