There are a lot of reasons that the Republicans will get tossed out this November and in 08. Iraq, a shaky economy, Bush's disapproval rate and scandals, etc.
Malaise at home and abroad is nothing new---just look at Carter's administration for proof. The Energy Crisis in the 70s led to Carter's poll ratings sinking lower than Nixon's in the midst of Watergate. And the Carter comparison brings to mind the nail in the coffin:
HIGH GAS PRICES