President Barack Obama has warned Russia there would be "costs" for any military intervention in Ukraine. President Vladimir Putin has evidently decided those costs are worth paying.

"They talk and talk, and then they'll stop," Oleg Panteleyev, a member of Russia's upper house of parliament, said Saturday, noting that the West made threats that came to little when Russia waged wars in the past in Chechnya in the early 2000s and Georgia in 2008.

He may have a point. With military intervention being ruled out, the West's response will have economic, political and security dimensions—but will be largely symbolic, Western officials and analysts said.

"I don't think the West has many options to pressure Putin to step back from the brink," said Eugene Rumer, an expert in the region who stepped down from the U.S. National Intelligence Council at the end of January. "I don't see economic sanctions being implemented in an effective manner."

The chill in relations is likely to linger longer than the frisson that followed Russia's invasion of Georgia in August 2008. Ukraine, larger and more important, borders directly on NATO and the European Union. Russia's actions in Ukraine are also widely seen as unprovoked—whereas many governments believe Georgian leader Mikheil Saakashvili was at least partly to blame in 2008.