Actually the Democrats did that by their own volition, through the mainstream media.
The large majority of the voters saw that the Democrats were soft on terror, saw the Democrats siding with the terrorists, realized the Demorats were against the war in Iraq (thought it was and still is wrong), saw the Democrat acting goofy on a variety of issues, realize Democrats have long been supportive of gay marriages, knew the Democrats had a history of supporting abortion, saw that the Democrats supported the killing of Terri Schiavo, were engaged in judicial activism all across this country, against free speech, against freedom of religion, against an ownership society, for higher taxes, and were smart enough to figure out that 2+2=4. Many of these brilliant people, like Zell Miller, have been lifelong Democrats. They themselves don't support the far left of the Democrat party.
The Democrat party leadership has demonstrated that they can't be trusted with the rod of power.
Have you considered how it was that so many people became aware of this? Was it trough the mainstream media, or was it through people like Michael Savage? You don't have to bother answering, I already know.