Obviously the war in Iraq has become VERY unpopular, as well as less and less connected to the terrorist attacks of 9/11 in the public's mind.
Corruption and ethics from Delay to Coingate to the CIA/Plamegate leak, not too mention all the electoral shenanigans, also are gaining a resonance with the public that won't go away.
The encroachments of the Patriot Act and the horrors of government-sanctioned torture will be a huge rotting carcass around the neck of the entire War Party.
The religious extremism and hypocrisy of the Schiavo case and the upcoming Roberts' SCOTUS hearings will be cutting the GOopers from both the left and the far right.
But there's one more deeply Republican theme where we can take the battle to the enemy and hit them hard: tax cuts.