Immigration gets a lot of media attention, and is a source of obsession for many politicians. A new USA Today/Gallup poll reminds us what we've known for years (and which my dad and I discuss in our book) but which you wouldn't know by listening to the rhetoric of the presidential race: Americans aren't nearly as concerned about immigration as commonly portrayed. It's certainly relevant, but just low on the list.
The easy answer is that given the Republican primary, this is all about the base. But an exit poll in Arizona--supposedly ground zero of anti-immigrant sentiment--showed only 13% of primary voters considered immigration the most important issue.
Further, if we break down the USA Today/Gallup results by party, we see that even Republicans rank immigration very low as an issue of importance for deciding their 2012 presidential vote.
These results tend to play out at the state level as well. For their own reasons, politicians at all levels play up immigration as if it were a major concern for voters (very often using the phrase "the American people"). This gets reported widely, and then copied by other politicians.
Exactly why is a matter for debate, as there are many possibilities that vary according to what level we're analyzing. They may truly believe that Americans agree, or may figure enough of their constituency does to emphasize immigration as an issue. Or they just emphasize it because it's a pet issue and they don't care whether others agree or not. And the media, of course, loves controversial human interest stories.
Regardless, it's important to remember that immigration is rarely as high on the list of "the American people's" priorities as we often hear in the media and from the mouths of politicians. In the 2012 presidential election, they are going to vote in large part on the economy, not on immigration.