Wars are won on the home front. We learned this in World War II. The soldiers fought bravely and hard, but what really won the war was the economic and industrial power that translated into planes and tanks and ammunition. And the great amplifier of our economic strength was sacrifice, both voluntary and enforced. People could not buy anything they wanted whenever they wanted it. Food and gasoline and other products were rationed. of food Roosevelt asked Americans to sacrifice, and they did.

Americans have not been asked to sacrifice much in our last few military adventures. We haven’t been asked to conserve gas or buy war bonds. Nobody has suggested that we should do without luxuries to help the war effort. Some people, of course, were asked to make the ultimate sacrifice and die in the line of duty. The general population, however, was simply asked to go shopping more.

And now Vladimir Putin has invaded the Crimean Peninsula and staged an election which, to the surprise of absolutely nobody, turned out to be a landslide. Let’s no kid ourselves. Putin is a dictator. But, as chess-master-turned-opposition-leader Garry Kasparov explained in an excellent editorial today, he is a dictator with “open access to international markets and institutions.” He can sell all the stuff he wants, and, so far, nobody has been willing to stop him by not buying it. “Rule like Stalin, live like Trump,” quips Kasparov, and the West has learned to be OK with that because it’s good for business.

Now that Putin has done the sort of thing that dictators often do—invaded a sovereign nation and annexed part of a country—the West is in a difficult position. We can stop him now, but only by imposing sanctions that completely isolate Russia from the world markets—and that will be bad for business. It will mean sacrificing stuff—something that Americans have not had to do in any real way since World War II.

The occasional call for military action by the likes of former Vice President Dick Cheney miss the point entirely. Military force, when possible, is the easy way out of tough international situations—the way that does not call on the entire population to make sacrifices. But wars between great powers in the 21^st century will not be won by blood. They will be won by treasure. Lots of treasure. And by a home front willing to forego economic advantages in order to compel dictators to keep their hands off of sovereign states.

We have heard over and over again that Putin invaded Crimea because he thought that America—and Obama in particular—was weak. In a sense, this is true. But it is not true militarily. Anybody with a map and a basic knowledge of Russia’s nuclear capabilities can see that Putin will not be forced out of Ukraine by American military might. And America has shown plenty of willingness over the last fifteen years to use military force to achieve its foreign policy objectives.

Putin believes that the people of America and Western Europe are too addicted to cheap oil to mount any serious economic sanctions. He does not believe that we will endure $8.00 a gallon gasoline, or a diminished market for our goods, in order to sustain the kinds of sanctions that will be necessary to force his hand. And apparently he thinks that we will convince ourselves that a referendum on a hotly contested issue, in which he essentially counted the votes, yielded a 96% vote in his favor--a rounding error away from the recent Glorious Leader vote in North Korea. Putin knows that we have to pretend to accept the legitimacy of this election, or we will have to do something about it that we simply lack the economic will to do. And I strongly suspect that he is right.