I can see why Obama would ask Arizona Gov. Janet Naplitano to head Homeland Security — she's about as close as any Democratic governor can get to appearing hawkish on illegal immigration. Of course, there's little substance to that appearance — yes, she was for using National Guard in support roles on the border and declared a bogus "state of emergency" on the border in 2005 mainly for the news coverage, but she's also against fencing on the border, vetoed a slew of bills intended to bring about attrition of the illegal population, including a ban on recognizing the matricula card and one that would have made illegal immigration a violation of the state's trespassing law, and only signed Arizona's tough employer-sanctions law because she feared voters would pass an even tougher one by referendum if she didn't.
The interesting political question is why she'd take this job. She's been considering running for McCain's seat in 2010 or Kyl's in 2012 — I can't see how she could go to Washington and start running for Senate in less than two years, so maybe she has 2012 in mind instead. But even so, as DHS secretary, she is now going to be answerable for every illegal alien crossing the border and every snafu at ICE or USCIS — like the recent revelations from Houston that immigration authorities allowed back into the community violent criminals who admitted they were illegal aliens.