It isn't possible for someone to simultaneously run for a high public office and clean up the national party.

Besides, the Democratic party is long past being redeemable. It is too corrupt. If people can't see that after the last 15 years under the Clinton/Gore/McAuliffe/Daschle/Pelosi/Democratic Leadership Council strategy of corrupting from within, then they don't want to see it, because it's easier to just keep voting Democrat than it is to do the hard work of convincing one's fellow Americans that the time has come for a progressive left political movement to move into the mainstream and seize the day.