So why is naturalization so low among Mexicans specifically? Pew provides several possible explanations.
One reason is that Mexican immigrants maintain close ties to their home country -- literally -- due to its geographic proximity. Another is that Mexico did not allow its citizens to hold dual citizenship until the late 1990s, so Mexicans who didn't want to give up Mexican citizenship may not know that they can now hold both simultaneously. According to the Pew report, 18 percent of Mexican immigrants said Mexico does not allow dual citizenship and 11 percent didn't know.
The cost is also prohibitive for some. It's gone up dramatically since July 2007, when U.S. Customs and Immigration Services almost doubled the fee. Mexican immigrants are more likely to live in poverty than other Latino immigrants, and are thus more likely to find the costs burdensome.
Obviously, Mexico will continue to be physically close to the United States, so Mexican immigrants may always feel more of a geographic pull than other immigrants. But should immigration reform pass, a number of advocacy groups have said they will be ready and willing to help people navigate the application process. The rhetoric and public opinion surrounding immigration reform are also more pro-migrant than they were in 1986, and some groups have even pledged to help raise funds for those who cannot afford the application fee.
Whether immigration reform passes this year or even in the next several years is still a huge question mark. And any estimates about how many Mexican immigrants might seek citizenship is only speculation. However, even with the changed rhetoric and growing momentum behind reform, the idea that all immigrants will seek citizenship is clearly no guarantee.