At this moment Santorum has the best stance on immigration. An incredibly important issue for me as a Californian that I cannot ignore. See the link below for the latest rankings by NumbersUSA.
https://www.numbersusa.com/content/action/2012-presidential-hopefuls-immigration-stances.html
As Santorum Surges In Iowa, A Pause To Check His Immigration Profile
By Roy Beck, Updated Friday, December 30, 2011
https://www.numbersusa.com/content/nusablog/beckr/december-29-2011/santorum-surges-iowa-pause-check-his-immigration-profile.html