To win, you have to get the base enthused enough to donate money, time, and energy in support of the candidate. Say what you want about Obama, he had the ability to get lots of people enthusiastically pulling for him.
A liberal-moderate will vote liberal rather than conservative-moderate. We saw that in this election.
I think I see your point now. Nevertheless, I have a different set of convictions wherein the greater of two evils must not allowed to rise to power. IMHO, to do otherwise is abetment.