The latest Rasmussen poll shows Fred Thompson doing better than John McCain in a potential presidential match-up in McCain's home state of Arizona, leading her by 17 points while McCain would only lead her by 10. Rasmussen speculates that immigration may be one reason for this difference:

The immigration issue which caused McCain trouble earlier in the summer is still powerful in his home state. Seventy percent (70%) of Arizona voters say it is Very Important to improve border enforcement and reduce illegal immigration. McCain was a visible advocate of the Senate “comprehensive” reform legislation which failed due to strong public opposition.

When it comes to legalizing the status of those already in the country illegally, just 20% consider that a Very Important issue.

Only 13% of Arizona voters believe that the federal government is doing enough to reduce illegal immigration. Eighty-two percent (82%) favor forcing employers to fire workers with false identification documents. Two-thirds (68%) say that people looking to rent an apartment should also be required to show identification and prove they are in the United States legally. These views are similar to those held by voters nationwide and are also similar to results found in our last Arizona poll, conducted in June.

McCain' favorable rating (48%) in Arizona is 10 points lower than Thompson's (58%) and 9 points lower than Giuliani's (57%). Clinton has a 41% favorable rating there.
McCain may be having other polling/electoral problems, too.

UPDATE: Another interesting thing about this poll (and, granted, this poll was taken over a year from the day of the election) is how strongly the Republican candidates--particularly Fred Thompson--are running against Clinton. Bush carried AZ by almost 7 points in 2000 (51-44.7) and by 10 points in 2004 (54.9-44.4). With Thompson running at a 17-point lead over Clinton, he has over double Bush's victory margin in 2000 and 170% of Bush's margin in 2004. Even the weakest candidate against Clinton according to Rasmussen, Romney, still has a 7-point edge over Clinton. At 51%, Thompson's level of support isn't up to Bush's 2004 yet (there are more undecideds), and AZ has very rarely voted for a Democratic presidential candidate over the past fifty years, and this is still a very early poll and so much can change over a year and Clinton might not even be the nominee, but perhaps this high level of support for Thompson (and the other R candidates) compared to previous elections might be offer a slight ray of hope for some gloomy Republican pundits.