He may not be the first person to blame, but Barack Obama deserves some criticism for letting the Arizona immigration law befall us. If he had left Janet Napolitano as Arizona governor instead of putting her in charge of Homeland Security, there's no way this law would've passed. Instead, Jan Brewer took office, signed it, and is now saying that her state is under terrorist attack from illegal immigrants.
Additionally, we could've had Napolitano as a Senate candidate. How that would've affected John McCain's votes over the past year and the 2010 Senate outlook is left as an exercise for the reader. The smart thing would've been to have somebody else do Homeland Security with the understanding that they might be asked to step out in two years, and that the Cabinet job would be Janet's then if she put in a good showing but lost her Senate race. Similar things apply, mutatis mutandis, to Kathleen Sebelius at HHS and Tom Vilsack at Agriculture.