Lenin, a Russian leader as obsessed with history as Vladimir Putin, famously said: “There are decades where nothing happens; and there are weeks where decades happen.” This has been the latter. The little more than a week since Russian troops invaded Ukraine has indeed shaken the world. Change has been telescoped, national taboos broken, moribund institutions given purpose and the spectre of a nuclear war in Europe has been raised for the first time since the 1980s. Germany has called it Zeitenwende, the turning point. It will not just be Ukraine that is changed for ever by this war.

But there is something specific about how war accelerates change. In The Deluge, his classic work on how society is changed by war, the British historian Arthur Marwick wrote: “War acts as a supreme challenge to, and test of, a country’s social and political institutions. War results not only in the destruction of inefficient institutions (such as the Tsarist regime in Russia), but also in the transformation of less efficient mechanisms into more efficient ones”.

The west has surprised itself with its ability to respond to the misery inflicted on the people of Ukraine. All kinds of unimaginable images emerge. The German Bundestag cheered an extra €100bn (£82.4bn) on defence spending, followed by 100,000 people on the streets in protest at Putin. Matteo Salvini, the great Italian defender of Putin, bringing white tulips to the Ukrainian embassy. Liz Truss, the UK foreign secretary, attending a meeting of the EU foreign affairs ministers meeting. The Hungarian leader, Viktor Orbán, sharply criticised by human-rights groups and others over the years for his hardline border policies, sitting on a school bench opening his arms to refugees.

It was just a fortnight ago that the German foreign minister, Annalena Baerbock, had appeared at the Munich security conference to caution the crisis was not the moment to try to execute an 180-degree turn on the decades-old German policy banning the sale of arms into conflict zones. Josep Borrell, the EU external affairs chief, batted away calls for Ukraine to join the EU, saying they already had an exceptional trade deal. He spoke about the “power of the EU’s language”, distancing himself from his own one-time claim that the EU must learn “the language of power”.

The next day – Sunday – all the talk was of Emmanuel Macron’s diplomatic initiative, and the concessions the French president had extracted from Vladimir Putin. Even on Wednesday, on the eve of the invasion, Baerbock gave an interview saying it was impossible for Germany to impose the strongest sanctions because of “the massive collateral damage” to Germany’s own economy. Putin could end up laughing at us, she warned.

Yet by the following weekend, two days after the invasion began on Thursday, Germany’s coalition government had started that 180-degree course correction. Chancellor Olaf Scholz and his cabinet agreed to send Ukraine 1,000 anti-tank weapons and 500 anti-aircraft Stinger missiles, lifting restrictions on German weapons being sent to conflict zones by third parties in the process. The next day, Scholz told the Bundestag in his trademark matter-of-fact manner that he was injecting €100bn into German defence, but protecting other budgets, and defence spending would rise above 2% of German GDP. The MPs from government and the CDU gasped and cheered in equal measure. David McAllister, a leading figure in the German CDU and chair of the European parliament’s foreign affairs select committee, admits he nearly fell off his chair when he heard the plans.

The promised growth catapults Germany into becoming the third largest spender on defence globally, behind only the US and China. GlobalData forecasts an annual German defence budget of $83.5bn in 2024, equating to a 45% increase on 2021’s budget of $57.5bn. That is bigger than France and the UK. Overnight Germany became not just an economic but also a geopolitical powerhouse. Polls said 78% of Germans backed the decision.

Matthias Matthijs, Europe senior fellow for Europe at the Council on Foreign Relations, said: “It is quite astonishing how fast this government broke pretty well every taboo in postwar German foreign policy.”

He attributes the scale of the change to a visit to Berlin on Sunday by the Polish prime minister, Mateusz Morawiecki. “I came to Berlin to shake the conscience of Germany,” Morawiecki said.

Sophia Besch, from the Centre for European Reform, points out Scholz himself insisted he had not acted due to pressure from allies, but due to Germany changing its view of the threat posed by Putin. “The truth is the world did not change last Thursday,” she said. “Berlin for years has ignored the warnings that came from many of our allies and from Putin. We need to learn the lessons of how this could have happened and how we could have been so blind. We are leaving behind some of our old beliefs – that economic interdependence prevents conflict, but I am not sure we know yet with what we are replacing this belief.”

Sergey Lagodinsky, a German Green MEP, argued Germany needs not only to spend more money, but to shift its mindset without becoming militaristic or interventionist. It needs to discuss how to adopt escalation, including military escalation, as leverage as part of its foreign policy toolbox. Foreign policy is not just a peace policy, Friedenspolitik in German, but also the ability to deal, manage and face conflict.

But the new German coalition, faced by the need to extricate itself from Russian energy, may have to challenge other orthodoxies. The Green economics minister, Robert Habeck, does not rule out extending the use of coal-fired power plants. “This blind, naive, one-sided relationship of dependency on Russia for energy for decades is one of the biggest strategic mistakes of the past 20 years,” Lagodinsky said. “Now we are stuck. It represents a medium- and long-term problem”.

But Putin’s recklessness is not just causing a revolution in Germany, but across Europe.

Sweden abandoned its policy of not sending weapons to conflict zones, agreeing to send Bofors AT-4, a single-use anti-tank launcher, to Ukraine, plus medical supplies. In Finland, a bombshell poll showed 53% want Finland to join Nato. “This poll flipped everything on its head,” said Charly Salonius-Pasternak, of the Finnish Institute of International Affairs. Moreover the poll showed that if voters were told that politicians said they backed the plan the support went up to two-thirds. “You could sense the president, Sauli Niinisto, realised the whole defence dynamic was changed.” Niinisto, seen as one of the best readers of what Putin is thinking is now rushing to hold urgent talks with Joe Biden in the White House.

Even in Switzerland, leaders had to catch up with the public mood in the space of a weekend, and by the Monday an emergency cabinet promised to implement the entire EU sanctions package. The decision does not formally end a policy of neutrality that has survived two world wars, but there is now pressure to track down the many oligarchs that live in the country. There are also calls for an increase in the defence budget

There has been a mini-revolution in Italy, too, where the prime minister, Mario Draghi, accused last week of seeking sanctions carve-outs to protect Italy’s dependence on Russian gas, has also found some mettle. He told parliament on Tuesday: “Yes, we want peace, but it is obvious that whoever amassed more than 60km of tanks near Kyiv does not want peace. We cannot turn our backs on Ukraine. Italy does not intend to look away.” He proposed an international public register of those with assets of more than €10m. In France, Macron looks likely to be re-elected comfortably next month as the rightwing candidates find themselves compromised by links to Putin they cannot deny.

Eastern European countries, sometimes hostile to refugees, have instead had the most open arms. Poland has taken an unprecedented 600,000 people. Orbán the Hungarian leader photographed smiling at child refugees, vows “No one will be left uncared for.”

The UK too has been experiencing unusually heavy traffic on the Road to Damascus. The Conservative government promises there will be no hiding place for oligarchs, publishing the delayed economic crime bill and seemingly unnerving Roman Abramovich into selling his stake in Chelsea football club. The endless denigration of Brussels has stopped. “The quality and intensity of the contacts between the EU and UK has been different to anything since before Brexit,” one EU official said. “We have restored a level of trust”.

But it has been at the level of the European Union that the action has been quickest and most surprising, revealing Ursula von der Leyen, the head of the EU Commission and former German defence minister, as a powerful advocate for action. For the EU to release €500m from the European Peace Facility to provide equipment and supplies to the Ukrainian armed forces, including – for the first time – lethal equipment, was a first. EU military staff based in Poland are now coordinating military supplies into Ukraine. The EU as a military player is no longer just the stuff of seminars.

Equally, the Commission in discussing its EU sanctions package acted with an unparalleled speed, and by consensus among the member states. Some EU sanctions packages take months to be agreed as one country or other exploiting the requirement for unanimity uses their veto power to pursue a national interest.

That the UK, US and EU were able to coordinate an attack on the Russian central bank, freezing out some Russian banks from the global Swift bank payment system and implementing measures to prevent Russian banks and firms raising capital, showed a wholly unexpected level of resolve. This was a financial declaration of war – an attempt to turn Russia into a pariah economy – something never tried before, using methods never deployed before. It involved, for instance, some G20 central banks freezing the Russian central bank reserves held in their own jurisdiction, so depleting the war chest of reserves that Putin had accumulated to defend his economy if it came under western attack.

All this is remarkable, indeed epoch-making, but not a cause for celebration. The institutions of liberal democracy may have belatedly shown resolve and unity, but in the here and now they are still losing. Keir Giles, from the Chatham House thinktank, is blunt: “Russia will want to present Zelenskiy with an appalling choice – whether to fight on at immense human cost and to the destruction of his country, infrastructure and economy or to submit to his terms in order that life can go on.

“The decision to abandon Ukraine to that fate was made by the west when it gave the green light to Putin by reassuring him that no one would intervene. Nato does not have a strategy to win the war in Ukraine because Nato does not want to be in the war in Ukraine.”

European politicians will also be worrying as the price of bread and energy soars in the months ahead whether voters are willing to make the sacrifice.

the Lithuanian foreign minister told the UK foreign affairs select committee that half-measures would not do. “Putin has no boundaries to what instruments he is going to use and unleash against the Ukrainians”, Gabrielius Landsbergis, said, adding the west “had to go all-in”.

He wants humanitarian corridors supported by no-fly zones. But the UK and the US have firmly rejected this since it would pit Nato pilots against Russian pilots. A Polish plan, backed by Borrell for Nato to provide Ukraine with Nato jets, training and bombs, got shot down in less than a day.

The other remaining option is to end the final carve-outs in the sanctions regime. “The push is now for carpet sanctions to match the carpet bombing,” said Orysia Lutsevych from the Ukraine Forum, adding the UK, EU and the US are still buying more than €700m of oil, gas and other commodities that is the equivalent of 150 tanks a day that Russia can finance.

That could be stopped either through an energy trade embargo, or by reversing the EU decision to let Gazprombank and Sberbank, the vehicles through which Europe pays for Russian oil and gas, stay in the Swift payment system. UK officials briefed on Wednesday they want to abolish the carve out given by the EU. If these two banks are thrown out of Swift that might immobilise Russian oil and gas exports, or lead to unspecified retaliation by Putin.

The breadth and range of economic and financial measures taken against Moscow, not to mention growing sporting and cultural isolation, has been a humiliation for Putin, but it is also a risk for the west if the Russian leader sees no answer but total victory.

“He is in a corner, but unfortunately with nuclear weapons, says Giles.

The west has been transformed in a week, but the question this weekend is if it would be willing, forced by the chaos of events, to go even further. The charge facing the west after a week of war is the one made by George Orwell of Neville Chamberlain in 1938. Like almost everyone at the time, he “neither wanted to pay the price of peace nor that of war”.