Alan Keyes apparently set the floor at 27%, which is not far below 30%
> Obama vs. Alan Keyes. ... Keyes was plainly, obviously, completely crazy. But 27% of the population of Illinois voted for him. They put party identification, personal prejudice, whatever ahead of rational judgement.
https://kfmonkey.blogspot.com/2005/10/lunch-discussions-145-...
https://en.wikipedia.org/wiki/2004_United_States_Senate_elec...
And lizardman's Constant is 4% https://en.wiktionary.org/wiki/Lizardman%27s_Constant