@engineer,
engineer wrote:But there is justification because the distribution of political leanings is much more the bell curve and Edgar is on one extreme. If Edgar thinks his protest will cause the Democrats to swing left at the expense of 3 or 4 Phoenixs he's mistaken. If he finds a candidate out there that supports his views, great but if he thinks by excluding his representation from the Democrats he is going to move them his direction I think the opposite is true. Edgar is working against his political aspirations by in effect supporting a party who represents everything he is against.
If you're suggesting that
Edgar (or any other disaffected former Obama supporter, such as myself) would have more influence inside the Democratic Party than voting for a third-party candidate, I think you're mistaken.
First, if you're right that the party would prefer somebody within one SD from the mean, like
Phoenix, over somebody who is at the end of the left tail of the bell curve, like
Edgar, then it really doesn't matter if he's attempting to influence things from the inside or the outside, since he's going to be ignored regardless of which side he's on. Better, then, to be welcomed by a small, ideologically congenial party than dismissed by a centrist, "big tent" party.
Second, it's often easier to influence a big party through support of a small party than to influence a big party through membership in a marginalized faction of that party. Ideas like direct election of senators, the income tax, women's suffrage, primary elections, referendum and recall, the forty-hour work week, and a whole host of other things that we take for granted were initially proposed by third parties. If leftists want to influence the Democratic Party in a more leftward direction, the worst way to do it would be to keep voting for Democratic candidates.