President Obama attempted Wednesday to rouse Europe to confront Russia’s military seizure of Crimea, framing the West’s dispute with Russian President Vladimir Putin as a clash of ideologies lingering from the Cold War.

In an evening speech at the Palais des Beaux-Arts, Obama made a broad case for U.S. and European unity, for sanctions against Russia that could damage still-fragile European economies and for help leveraging American power that he made clear in this case does not include military force.

Using the museum as a cultural counterpoint to Russia’s display of force against Ukraine in recent weeks, Obama stressed that Moscow’s moves endanger not only that country but the international system that Europe and the United States have built over the years, a system that has been vital to the progress of democracy and international law worldwide.

“Now is not the time for bluster,” Obama told an audience that, as has become his practice abroad, consisted mostly of young people. “The situation in Ukraine, like crises in many parts of the world, does not have easy answers, nor a military solution. But at this moment, we must meet the challenge to our ideals — to our very international order — with strength and conviction.”

Echoing themes from a similar speech against complacency that he delivered last year in Berlin, Obama warned the European public, which he conceded might view Ukraine as a distant problem, that “we cannot count on others to rise to meet those tests.”

“The policies of your government — the principles of your European Union — will make a difference in whether or not the international order that so many generations before you have strived for continues to move forward, or whether it retreats,” he said.

Obama’s address here provided the central message of his three-country tour of Europe, and it began as a specific accounting of the West’s political values and how those contrast with Russia’s annexation of Crimea after a referendum that much of the world has called illegal.

The roughly half-hour speech ended largely as an argument with an absent counterpart — Putin — with Obama raising the Russian president’s arguments for military intervention in Ukraine and then rebutting them for a crowd more rapt than rowdy in the formal setting.

Touching on 20th-century European history, the decolonization and democratization of the developing world, and the United States’ own civil rights movement, Obama warned that the political progress and prosperity known by this generation of Europeans are not secure from the “older, more traditional view of power” that Putin is employing along his borders.

“I come here today to insist that we must never take for granted the progress that has been won here in Europe and advanced around the world,” Obama said. “Because the contest of ideas continues for your generation. And that is what’s at stake in Ukraine today.”

Staying within the system

One of the more surprising moments came when Obama used the Iraq war to argue that, even when seeming to stray from the values he celebrated, the United States has attempted to act within the international order.

Obama, then an Illinois state senator, opposed the 2003 invasion of Iraq — calling it a “dumb war” — and his comments here amounted to the most generous accounting of the conflict he has delivered in office. His opposition helped propel him through a crowded Democratic primary field in 2008 and, eventually, to the presidency.

“Russia has pointed to America’s decision to go into Iraq as an example of Western hypocrisy,” he said, noting his opposition to the war. “But even in Iraq, America sought to work within the international system.”

Addressing a continent strongly opposed to the Iraq invasion, Obama said the United States “did not claim or annex Iraq’s territory, nor did we grab its resources for our own gain.”

“Instead, we ended our war and left Iraq to its people, and a fully sovereign Iraqi state could make decisions about its own future,” he said, adding that “neither the United States nor Europe are perfect in adherence to our ideals.”

“We are human, after all, and face difficult choices about how to exercise our power,” he said.

Obama made the remarks after warning European leaders earlier Wednesday that nations must “chip in” fairly to ensure a NATO capable of deterring an expansionist Russia, and he placed the responsibility largely on the continent to resolve its dependence on Russian energy.

Speaking at a news conference after meeting with European Union leaders, Obama noted that he has been concerned about declining defense budgets among some NATO members, a complaint he has allowed other administration officials to make in the past.

His words were a pointed reminder that despite U.S. involvement in seeking to prevent Putin from advancing farther beyond Russia’s borders, European leaders must be ready to pay more for their defense.

“If we have collective defense, it means everyone’s got to chip in,” Obama said, appearing after meeting with Herman Van Rompuy, president of the European Council, and José Manuel Barroso, president of the European Commission. He spoke a day after he called Russia a “regional power” that, after having annexed Ukraine’s autonomous Crimea region, is threatening its neighbors in a sign of weakness rather than strength.

Obama cited declining “trend lines” in defense spending among some NATO members, cutbacks he called expected given the financial straits that many European nations have faced over the past five years.

But he said NATO members must recommit to defense spending, especially as the United States enters the final months of its wars that began after Sept. 11, 2001.

Obama met later with NATO Secretary General Anders Fogh Rasmussen, where the president pledged to help increase ground, air and naval forces as part of NATO operations, particularly in Eastern Europe.

On Wednesday, Barroso called Russia’s move on Crimea “a real wake-up call” for European leaders on the issue of energy. Although Obama pledged in the meeting Wednesday to help Europe think through energy strategies — and held out the potential of expanding U.S. natural gas exports to Europe — he made clear that Europeans must manage the bulk of the burden.

“We have to do also our own work here in the European Union,” Barroso said.

International spotlight

Over the course of his presidency, Obama has looked to the big stage, particularly the international stage, to set out challenges (Prague in 2009 when he outlined his aspiration to rid the world of nuclear weapons), change the tone of U.S. diplomacy (Cairo two months later when he asked the Muslim world for a “new beginning”), or explain himself (Oslo late that year when he argued in support of “just war” in accepting the Nobel Peace Prize).

Less than a year ago, Obama spoke before the Brandenburg Gate, the first U.S. president to do so from what had been East Berlin. He celebrated the wall’s collapse, along with Cold War geopolitics.

The president began Wednesday moving back even further into Europe’s 20th century — visiting Belgium’s Flanders Field 52 miles west of Brussels to lay a wreath at a memorial for the 368 Americans killed on one of the grimmest World War I battlegrounds.

He spoke, briefly, alongside Belgian Prime Minister Elio Di Rupo and King Philippe, who guided him through the cemetery and fields, now sown with red poppies above the bodies of tens of thousands of fallen soldiers.

“It is impossible not to be awed by the profound sacrifice they made so that we may stand here today,” Obama said, adding that “here we saw that no soldier — and no nation — fought alone.”

Kathy Lally in Kiev and William Branigin in Washington contributed to this report.