It's a tricky situation, however. If a referendum does find that a majority of Crimean citizens want to join Russia, it could seriously undercut many of the arguments from Ukraine's new government. It would also act as a boost for the Kremlin, where intervention in Crimea has been justified by claims that ethnic Russians need protection from an illegitimate leadership in Kiev.
What's unclear right now is exactly how Crimea would vote in such a referendum. At first glance, it's easy to look at the widely cited census data from the region and predict that the large percentage of ethnic Russians in Crimea would vote to join Russia:
There is an important caveat to this chart, however – this census data is from 2001.
That's more than a decade ago, and given the fact that Crimean Tatars have only been allowed to return to the region since the fall of the Soviet Union (they were deported during World War II for allegedly collaborating with Nazi Germany), it's reasonable to think that their numbers might be up. Besides, as others have pointed out, people's opinions can't simply be boiled down to their ethnicity: Crimea had a referendum on independence from Russia back in 1991, when it was far more Russian than today, and it then favored being part of a newly independent Ukraine.
Instead, let's turn to opinion polls. One recent survey, conducted by the Ilko Kucheriv Democratic Initiatives Foundation together with Kyiv International Institute of Sociology, looked at what Ukrainians wanted from their relationship with Russia in the days before Viktor Yanukovych's removal from office. On the whole, the survey found, Ukrainians didn't want to be a part of Russia, but favored some kind of close economic relationship:
In Crimea, however, the numbers were significantly different, with a much larger percentage wanting to join with Russia (unfortunately, a more detailed breakdown of the other votes wasn't available here). It's definitely worth noting, however, that this is a plurality, not a majority: Something required in most states that use referendums to decide policy.
Over at the Monkey Cage blog, Grigore Pop-Eleches of Princeton University and Graeme Robertson of University of North Carolina-Chapel Hill have shared some of their research from Ukraine from January 2013 (well before the Maidan starts).
It's a fascinating post that you should read in full, but to give you an important glimpse of how Crimean citizens see themselves, it's worth looking at the chart below. It shows that those from Crimea are exceptionally unlikely to describe their homeland as "Ukraine," "Soviet Union" or "Russia" – instead, they are far more likely to answer "Crimea":
Pop-Eleches and Robertson also point to another recent poll, conducted in December by the Razumkov Center, which found that 56 percent of respondents were opposed to joining Russia or becoming an independent state.
Finally, given that Russia is playing such a large role in all this, it's worth looking at the opinions of Russians, too. This poll, conducted by a well-respected agency linked with the Russian state, found that a majority of respondents view Crimea as part of Russia.
There are a few fascinating elements to this one. First, it was conducted in August, long before Ukraine's situation blew up, so it appears to show some deep-rooted feelings about Crimea (which was, after all, part of Russia until 1954). It's also worth noting that in this poll, more people thought Crimea was a part of Russia than Dagestan (41 percent) and Chechnya (39 percent) – both of which are republics in the Russian Federation.
Ultimately, it's not clear what would happen in a fair Crimean referendum, but the information we have suggests that a majority in favor of joining the Russian federation isn't preordained. Whether the vote would actually be fair, of course, is another matter.