In one week of war, life within the boundaries of Ukraine has been upended, but the brutal assault Russian President Vladimir Putin launched last Thursday has reverberated around the globe as well, steering history in a new direction and switching up 75 years of relations among some of the world’s most powerful and wealthy countries.

In Germany, hundreds of thousands marched in support of the NATO alliance’s firm stance against Russia’s aggression and the Berlin government decided to send military aid to Ukraine - a dramatic about-face in a country that for more than seven decades has shied away from military involvements as a kind of penance for the Nazi genocide and World War II.

Throughout Europe - even in staunchly neutral Switzerland - countries that depend heavily on Russia to heat people’s homes and power their economies banded together to isolate and punish the Russians for their aggression. Countries that just a few years ago rose up in protest over the arrival of migrants fleeing wars and extremism in the Middle East, Near East and North Africa are suddenly welcoming hundreds of thousands of refugees.

In the United States, the war created a brief, almost disorienting moment of unity, as Democrats and Republicans alike - with the prominent exceptions of former president Donald Trump and some of his hardcore supporters in the media and politics - denounced Putin and embraced the Biden administration’s crippling sanctions against Russia.

“In the battle between democracy and autocracies, democracies are rising to the moment, and the world is clearly choosing the side of peace and security,” President Joe Biden declared Tuesday night in his State of the Union address.

In one week, the war in Ukraine has focused the world’s attention away from the coronavirus pandemic, away from inflation and supply chain problems, and away from more chronic problems such as climate change.

Regional wars often have a way of wreaking havoc well beyond the battlefields; Syria’s civil war, for example, similarly sucked in the United States, western European powers and Russia. But the war in Ukraine has almost instantly restructured global power dynamics, in part because of Putin’s nuclear saber-rattling and in part because the world has become so much more interconnected in recent years - in trade, technology, media and politics.

“In less than one week, you’ve seen a fundamental shift as Europeans realize they have to take on more responsibility for their own defense,” said Steven Pifer, a former U.S. ambassador to Ukraine who is now a fellow at Stanford University’s Center for International Security and Cooperation. “In less than one week, you’ve seen five decades of German attitudes toward Russia turned on their head.”

One day before the Russian invasion, Pifer said, “no one would have predicted this much change: the unity around strong sanctions against Russia, the German about-face, the Swiss joining the European Union in its sanctions, the American people rallying around the Ukrainians,” even across party and ideological lines.

Countries with strong ties to Russia have declined to join Western nations in imposing sanctions on Moscow, but have not fully endorsed Putin’s move, either. India, which relies on Moscow for most of its advanced weaponry, abstained from a United Nations vote to condemn the invasion. China called for a negotiated end to the conflict, though its foreign minister, Wang Yi, said “the Chinese side understands Russia’s legitimate security concerns.”

Putin’s aggression has put China hawks in the United States on guard. House Minority Leader Kevin McCarthy, R-Calif., on Tuesday night called for the United States to step up military support for Taiwan, so China doesn’t view the war in Ukraine as a sign that now’s the time to move against the island nation.

None of the concerted actions against Moscow have so far dislodged Putin from his goal of overthrowing Ukraine’s democratically elected government and forcing the former Soviet satellite state back into the Russian orbit. But in addition to isolating Russia from the world community and delivering an economic and geopolitical wallop to one of the planet’s three primary nuclear powers, the swift avalanche of nonmilitary actions against Putin has convinced many world leaders that global power dynamics have entered a phase of startling and perhaps enduring change.

War - and particularly the prospects of world war and nuclear conflict - has a unique power to change the behavior of people and nations. This war - viewed online around the world in searing video snippets showing courageous Ukrainians standing up against Russian tanks and residential neighborhoods charred and shredded by Russian missiles - has turned public opinion against Putin and Russia so quickly and overwhelmingly that demonstrations, fundraising drives and boycotts of Russian goods have at times outpaced governmental actions.

Perhaps the sharpest change has come in Germany, at the center of Europe. The country that started two world wars had managed, until this week, to keep its feet firmly planted in the West even as it maintained close ties with Russia. Germany simultaneously has relied on the NATO alliance to defend itself against Russia and has been highly dependent on Russian oil and gas exports.

Now, in a sudden shift brought on by the war in Ukraine, Germany has decided to provide lethal weapons to Ukraine, cut off key banking ties with Russia, suspend completion of a natural gas pipeline between the two countries and boost its defense spending by an unprecedented amount.

Just a couple of weeks after German politicians who supported sending a supply of helmets to Ukraine found themselves denounced as warmongers, 78% of Germans in a poll published Tuesday said they now support the massive increase in defense spending - a startling number given the German public’s decades-long allergy to the use of military force abroad.

Putin’s effort to push back hard against what he sees as an American and western European drive to dominate Europe and encroach on Russia’s traditional sphere of influence has backfired even among a German public that has long viewed Russia as a useful balance against U.S. power.

On the streets of Berlin, a massive crowd estimated at a half-million people demonstrated Sunday on behalf of Ukrainians, carrying signs such as “I’m ready to freeze for peace,” a reference to Germany’s reliance on Russian oil and gas for home heating. The German foreign minister, Annalena Baerbock of the Green party, which has strong pacifist roots, concluded that “perhaps on this day, Germany is leaving behind a form of special and unique restraint in foreign and security policy.”

German Chancellor Olaf Scholz, in office for only two months, said the West is now living through a “Zeitenwende,” meaning a turn in the times, a new era. Such a shift was especially striking for Scholz, a Social Democrat, because as a leader of his country’s Young Socialists movement decades ago, he had spoken out against “aggressive-imperialist NATO” and called for “overcoming the capitalist economy.”

But if Russia’s war on Ukraine heralds a new time, “what is this new era?” asked Jackson Janes, president emeritus of the American Institute for Contemporary German Studies at Johns Hopkins University. “Is this Cold War 2.0? There’s been a huge change in large parts of the world in one week, but is it sustainable? What if the gas gets turned off in Berlin? How long does this unity last?”

Whatever policy flips Germany makes now, “they still have to deal with the Russians,” Janes said. “The geography doesn’t change.”

If geographical proximity to the battlefront is making this war more frightening to Europeans - the arrival of more than a half-million migrants fleeing Ukraine for Poland and other neighboring countries is making the war feel even closer to home for many Europeans - then geographical distance may have an opposite effect on U.S. attitudes toward the war.

“We’ll have to see how long this coalition can hold together,” Janes said. “The economic pressures - inflation, energy - aren’t going away. The Europeans are glad we are all on one page right now, but every German leader I speak to says, ‘Yeah, America’s back, but for how long?’ They’re really afraid of 2024 and a return of Trump or a Trump-like figure.”

Trump, who has strongly indicated he intends to run again for president, has long admired Putin and praised his “genius” in the run-up to Russia’s invasion of Ukraine. He also has touted his “good relationship” with the Russian president, sowing doubt in capitals around the globe that America under his leadership would counter Russia as punishingly as the Biden administration has.

The global response to the Russian invasion has nearly paralyzed Moscow’s economy, but the conflict has also rattled markets worldwide, bolloxing up the flow of food and energy, and jeopardizing the recovery of supply chains and employment as the third year of the pandemic begins.

Although many Europeans say they’re willing to sacrifice on behalf of the besieged Ukrainians, it’s not yet clear whether that mood extends across the ocean, either in public opinion or among elected officials. Some Republicans in Congress returned for the moment to a traditional bipartisanship regarding defense policy toward a foreign war, but it was clear at Biden’s State of the Union address that any semblance of unity was fleeting, especially in an election year.

“We’re all together at this point, and we need to be together about what should be done,” Senate Minority Leader Mitch McConnell, R-Ky., said earlier this week.

But even Republicans who embraced Biden’s emphasis on tough sanctions against Russia made it clear that they do not intend to stop attacking Biden on all fronts, including foreign policy. “He’s letting Europe lead instead of America leading,” McCarthy told Fox News host Sean Hannity after Biden’s speech.

Even a world-rattling war doesn’t bridge the country’s cultural and political divisions and it remains to be seen how long public opinion - now showing large majorities of Americans supporting a strong U.S. response to Russia’s aggression - will remain unified. The war in Ukraine doesn’t negate efforts by at least three consecutive U.S. presidents to shift America’s foreign policy focus toward China and Asia.

Even if the American focus on Ukraine fades with time, Russia’s role in Europe and beyond cannot be ignored. And even though the United States doesn’t depend on Russian energy, much of Europe does. Russia produces about 10% of the world’s oil and gas, and Russia and Ukraine export about 30% of the planet’s supply of wheat, so war between those countries will continue to have a destabilizing impact far from Kyiv and Kharkiv.

In much of Europe, the idea that aggressive superpowers will have their way with smaller nations was taken as a given through much of history. But after World War II and particularly after the fall of the Berlin Wall in 1989 and the collapse of the Soviet Union less than two years later, many Europeans believed that by banding together in a European Union and aligning themselves with Washington in NATO, they had created a new dynamic in which brute force was no longer the primary factor in how nations competed with each other.

The war in Ukraine is testing that notion severely. Even if NATO allies and other countries that have lined up to put pressure on Russia in the first week of the war maintain their unity, it’s not clear that their coordinated efforts will have the desired impact.

At the least, the West has made it clear that Putin’s perception of weakness and discord in the world’s democracies was not wholly accurate.

For Putin now to see a united West lining up to take tough steps against him “should logically make Putin take a step back and reconsider what he’s done,” Pifer said. “But his narrative for a long time has been that the West is out to get him. Unfortunately, maybe this unified response confirms that narrative in his mind.”