The rapidly unfolding crisis in Ukraine will be decided primarily by two people: Russian President Vladimir Putin and German Chancellor Angela Merkel. So it was encouraging to hear Merkel say Thursday that if Russia goes further in destabilizing its neighbor, it will face “massive economic and political harm.”

What precisely that harm would be, she did not specify. Nevertheless, Merkel deserves credit for her warning, and the European Union and the United States should support her efforts to spell out the consequences to Putin for Russia’s aggression.

Germany has the most to lose from an economic showdown with Russia and, by the same token, the greatest capacity to influence and punish Putin.

Germany gets 35 percent of its oil and natural gas supplies from Russia, and its annual exports to Russia are worth $53 billion.

More than 6,000 German companies have investments in the country, and German business leaders say trade between the two countries is good for about 300,000 German jobs.

Merkel’s restraint has given other countries with much to lose from sanctions – such as Britain and the Netherlands – a place to hide.

The response that Merkel and the EU have promised for Monday if a phony Crimean secession referendum goes forward – visa bans and asset freezes for the Russian officials responsible – is relatively feeble.

Russia is preparing for the potential imposition of Iran-style sanctions by the U.S. that would cut off Russian banks from U.S. dollar transactions, and Merkel should commit to do the same in Europe.