Ukraine has been wracked by protests for two-plus weeks over President Viktor Yanukovych's decision to reject a deal for closer integration with the European Union. Thousands of protesters in the capital city of Kiev are calling for Yanukovych to step down.

This is a potentially big moment for Ukraine, as well as for Europe: Russian President Vladimir Putin had been pressuring Yanukovych to quit the EU deal and join with a Moscow-led trade union of former Soviet states instead. Will Ukraine's future be with Russia or with Europe?

What's happening in Ukraine is complicated and driven by many factors: the country's history as an unhappy component of the Soviet Union, its deep economic woes, a sense of cultural fondness for the West, wide discontent with government corruption, two decades of divided politics and a sense that Yanukovych caved to Putin.

No single datapoint could capture or explain all of that. But the map below comes perhaps as close as anything could. It shows Ukraine, color-coded by the country's major ethnic and linguistic divisions. Below, I explain why this map is so important and why it helps to tell Ukraine's story. The short version: Ukraine's politics have long been divided into two major factions by the country's demographics. What's happening right now is in many ways a product of that division, which has never really been reconciled.

Roughly speaking, about four out of every six people in Ukraine are ethnic Ukrainian and speak the Ukrainian language. Another one in six is ethnic Russian and speaks Russian. The last one-in-six is ethnic Ukrainian but speaks Russian. This map shows where each of those three major groups tend to live. (I'm rounding a bit on the numbers; about five percent of Ukrainians are minorities who don't fit in any of those three categories.)

Here's why this matters for what's happening in Ukraine now: Since it declared independence in 1991, the country has been politically divided along these ethnic-linguistic lines. In national elections, people from districts dominated by that majority group (Ukrainian-speakers who are ethnically Ukrainian) tend to vote for one candidate. And people from districts with lots of ethnic Russians or Russian-speakers tend to vote for the other candidate.

To see what I mean, check out these two maps that show the results of Ukraine's 2004 and 2010 presidential elections, both of which were very close. Yanukovych lost the 2004 vote (on the second round of voting, that is; the first round was annulled after protests over fraud allegations) by 52 to 44. But he won in 2010 by 49 to 45 percent. In both cases, you can see a clear and consistent regional divide. Maps of other presidential and parliamentary elections look very similar.

Ukraine's ethno-lingistic political division is sort of like the United States' "red America" and "blue America" divide, but in many ways much deeper -- imagine if red and blue America literally spoke different languages. The current political conflict, which at its most basic level is over whether the country will lean toward Europe or toward Russia, is like the Ukrainian equivalent of gun control, abortion and same-sex marriage all rolled into one.

Based on the protests in Kiev, it can sure look like Ukrainians want their country to integrate with the European Union and turn away from Russia. But a November poll found slightly different attitudes: 45 percent said they wanted the EU deal, 14 percent said they wanted to join with the Russian-led trade union, and 41 percent said they were undecided or wanted neither. In other words, joining the EU is about as popular as not joining the EU, both of which are more popular than snuggling up to Moscow.

It's a safe bet that ethnic-linguistic Ukrainians would be more likely to want the EU deal. Europe is often seen there as the alternative to Russia, so supporting EU integration is a little like supporting "not Russia."

These maps also show why it could be easy to overstate the protests and the degree to which they represent all Ukrainians. The mass protests, and thus most foreign journalists, are in the capital city of Kiev. You can see it in the map up top, in a little pink circle inside a sea of ethno-linguistic Ukrainian red. But President Yanukovych is from the eastern, more Russian part of the country, where he served as a regional governor for several years. In 2010, 74.7 percent of Kievans voted for Yanukovych's opponent; it's not shocking that they would want him to leave office.

Things are different in the other end of the country. As the scholars Kataryna and Roman Wolczuk wrote at Monkey Cage, "in Russophone Eastern and Southern Ukraine, Lenin is still respected by many, despite Communism’s obsolescence even there." This weekend, when protesters in Kiev toppled an old statue of founding Soviet leader Vladimir Lenin, some Ukrainians in the Russian-speaking parts of the country expressed outrage.

Here in the United States, we hear the same refrain from the minority party every time there's a major election: "Let's take back the country." The implicit perception, that the other side of the American political divide doesn't really represent the nation, seems to have some parallels in Ukrainian politics. Protesters in Kiev see Yanukovych's decision to reject the EU deal and embrace Moscow as a betrayal. Similarly, former prime minister and opposition leader Yulia Tymoshenko was imprisoned on (highly suspect) corruption charges over allegedly signing an oil trade deal that was too favorable to Russia.

The protesters out in the streets in Kiev are showing remarkably bravery and political will. They have some very real grievances that have nothing to do with ethnic or linguistic lines, particularly government corruption and the troubled economy. But what we're seeing is, in some very important ways, a function of a demographic divide that Ukrainian politics have never really bridged.