Quite frankly if people defected after hearing someone had an ancient DUI... somehow I doubt they would have gone Gore.
Rove estimates something like 3 million religious conservatives didn't show up on election day in part due to the DUI.
If Rove was accurate, that would mean that GW would have won a clear, comfortable, win in 2000. We would have avoided the Florida debacle and all the acrimony.
GW would have taken at least 301 EV to 237 for Gore, and GW would have had a lead in the popular of about 2,500,000.
Words can't even describe how much I doubt that.