Ending the Bush dynasty.... unless .... no, no, it's too awful to contemplate!
What's a legacy, anyway? Historical record, the long-term consequences of his actions, or his reputation, as promulgated by media pundits, upon leaving office?
The people who yell loudest about the debt, for example, are the very same people who ran up the bills, skimmed off the profit and demanded to be bailed out. The people who blame unemployment on the federal administration are themselves, or enablers of, the same people who have been steadily exporting industry for 30 years and cutting public service jobs. The people who complain most about taxes are those who don't pay any taxes. The people who are most against investment of public money in public works are the same ones who profit from government contracts. The people who rail against the shiftless poor are the very ones who cause poverty.
This is a standard rightist strategy: 1. steal all you can 2. when the economy is about to collapse, let a lefty win the election 3. prevent reform; make as difficult as possible for him to repair the damage 4. if some of the damage is repaired in spite of your most vigorous obstruction, take back the office, resume stealing.
Actually, Obama's legacy may not be worth mentioning in the face of the global cataclysm that's coming.