Arizona: McCain 47, Hayworth 36

Any incumbent who earns less 50% support is considered potentially vulnerable, and McCain has been hovering around that mark all year. Since January, McCain’s support has fallen in a narrow 47% to 53% range. Hayworth’s support has generally been in the low 40s.

Last month, McCain led Hayworth 52% to 40%.

The 2008 Republican presidential nominee cannot be comforted by the fact that his level of support in early primary polling is similar to the numbers for another veteran senator, Arlen Specter of Pennsylvania.