This is something I've been wondering about. It probably has an easy and obvious answer that I'm overlooking, or an answer that is well known, but I'll risk looking silly and ask anyway.
Suppose you are at the phase in a presidential campaign where the primaries have ended, and it's down to two candidates.
How do you get more votes, is it best to move people across the line in the middle, i.e. by capturing the undecideds, the independents, the cross-over votes, etc.? These are people who will vote in any case, it's only a matter of who they vote for. Or is it better to draw new voters to the polls, people who wouldn't have voted otherwise but are likely to vote for you if you can get them to show up?
If the goal is to move the middle, then a mild, centrist message would seem to be best. If both candidates pursued such a strategy, wouldn't it make for a relatively mild campaign, at least in comparison to a campaign where the goal is to draw people to the polls? However, when the goal is to motivate people to vote who wouldn't do so otherwise, it seems that a much shriller, polarized, vicious campaign would result (that sounds familiar).
I have in mind that the goals are often at odds, i.e. emphasizing issues that would draw voters of your political affiliation to the polls might lose voters in the middle, while targeting the middle may cause some voters at the extremes to become disenchanted and stay home.
In some cases it would be possible to do both, i.e. move the middle and excite people enough to draw them to the polls and vote for you. Other strategies could either bring in new voters without changing the middle, at least not enough to matter, or the reverse, move the middle without costing votes on the fringe. Some politicians are able to use language skillfully (or deceptively) along these dimensions, i.e. excite the fringes to the polls with coded language that leaves the middle relatively unaffected, or appease the middle without losing the fringe.
Policy positions that have these characteristics are easy, there are benefits but few if any costs, so they should be adopted (examples?). But often, it seems to me, the goals are at odds. So I'm wondering, which margin is most active, i.e. which margin is most responsive to targeted messages and thus produces the most benefits, the middle or the fringe?
As I noted above, my thoughts are not well-formed on this. Is there an obvious answer to which margin is most productive? Or should I be thinking about this in some other way?