>Plus people rarely back a candidate for single issues.

Tell that to all the black gun owners who vote R because they don't want wake up one day and find out they're felons or all the fiscal conservatives who vote D because they believe healthcare and the climate are bigger short term issues.

I generally agree with you that people back whoever pushes policy they like most but people also have deal-breakers that will cause them to back the other guy even if they don't like his platform.