MOSCOW—Grim predictions for the future of Russia’s economy swept over Moscow this week like shock waves.

The announcement by the U.S. State Department on Wednesday that it would impose new sanctions because of Moscow’s alleged attempt to murder an ex-spy in Britain with the chemical weapon novichok is only the latest trauma.

Russian papers, talk shows, and officials already were obsessing over the “ Defending American Security from Kremlin Aggression Act ” proposed in the U.S. Senate by Republicans as well as Democrats. Aiming to punish Russia for alleged meddling in U.S. elections and deter it in the future, the bill promised to ban major Russian banks, freeze operations by Russian gas and oil companies, shut down Russian botnets, and investigate President Vladimir Putin’s personal wealth, among other measures.

The ruble plunged: it is now 66.5 to the dollar, the worst rate since 2016. Fear of massive new sanctions caused Aeroflot shares to drop by 11.4 percent and other stocks to take a nosedive, although by Thursday evening the market recovered its losses. Meanwhile the public approval rating of Putin’s foreign policy continues to melt down, sliding into the teens.

In an interview with The Daily Beast, Yevgeny Gantmakher, one of Russia’s leading economists, said there is a certain predictability about the Russian president’s reaction: “Over the last 18 years we have learned one thing about Putin: he does not bend under pressure.”

Speaking metaphorically, the economist suggested Putin will behave like a one of the barons of old pulling back into his fortress: “His strategy for the next six years is to withdraw into his besieged castle, concentrate as much money inside the castle as he can extract from pensioners, big business, anybody—and give out ‘water and food’ in rations, watching how far he can push his strategy. My guess is that rations will be different for different people.”

Gantmakher is a member of the Russian Committee of Civic Initiatives which for years, led by its chairman, ex-minister of finance Alexei Kudrin, has been advising the Kremlin to reform the Russian economy, to respect the Russian constitution, to create independent, transparent institutions, fight corruption, and use new technologies and innovations.

In the past year some small steps have been made in those directions: the Kremlin began to investigate high-profile officials for corruption in several of Russia’s regions. But there has been no sign of big reforms.

With oil prices dropping below $70 a barrel, and Russia still dependent on hydrocarbons for more than 50 percent of the government’s revenue, as well as about 16 percent of GDP, Putin needs serious technocratic expertise to budget funds and watch spending. But that’s not likely to happen. “Putin knows that America’s new sanctions will push him to change his policies but he is not interested in changing, in reforming Russia,” said Gantmakher. “He and his propaganda machine are focusing on mobilizing the country now against the enemy.” That is, the United States.

“This is the biggest intrigue we are witnessing in Russia: the Kremlin building its besieged castle, dragging the country to the Soviet past, while the society, used to economic freedoms, is rejecting the castle strategy, hoping to move forward.”

According to the Levada Center, an independent, non-governmental polling and research group, public support for Putin’s foreign policy has dropped from 22 percent in 2016 down to 16 percent this summer. At the same time, fewer and fewer Russians say they trust Putin: in March, 55 percent of Russians said that they thought the president trustworthy; in July only 37.9 percent felt that way.

In reaction to the Senate bill and the Novichok sanctions, Russia threatened to stop using the U.S. dollar. Russian MPs and diplomats made bitter statements, accusing London and Washington of ganging up on Moscow. “The Russian side will work on developing retaliatory measures,” Maria Zakharova, spokeswoman for Russian Ministry of Foreign Affairs, said on Thursday.

When Professor Gantmakher heard that, he just shook his head: “I don’t think Putin has much to respond with to the new American sanctions,” he said. “Even after his friends, oligarchs Oleg Deripaska and Viktor Vekselberg, were punished by the U.S. sanctions, Russia did not respond.”

The present and proposed sanctions will kick in over a period of months. The real economic siege of Putin’s castle has only just begun.