In 1948 I entered the Massachusetts Institute of Technology, undecided between studies of chemistry and physics, but my first year convinced me that physics was more interesting to me.
We didn't want to waste time by sending our volunteers to Republicans; we sent them to the undecided.
Campaigns fail if they waste resources courting voters who are unpersuadable or already persuaded. Their most urgent task is to find and persuade the few voters who are genuinely undecided and the larger number who are favorably disposed but need a push to actually vote.
One of the enduring myths of campaign analysis is that you can actually count the number of 'undecided' voters by asking voters if they are undecided or not. Sometimes, significant numbers of voters actually change their minds.
I'm not a policy wonk - I'm somewhere between being undecided and a surrogate.
I am undecided whether or not the Milky Way is but one of countless others all of which form an entire system. Perhaps the light from these infinitely distant galaxies is so faint that we cannot see them.
Pre-poll surveys receive different reaction in the media among voters and political parties. For example, the more undecided voters are, the greater the role and effect of pre-poll surveys. Similarly, greater the decline of the party system, the more influential their role.
That's the trouble with trying to influence an undecided voter. First you have to find one.