Control of elections begins long before the voting actually occurs though the actions of the coalition of parties-in-government principally in their legislative and judicial capacities.
An excellent overview how how this came about is presented in a paper by Adam Winkler " Voter's Rights and Party Wrongs" here: http://papers.ssrn.com/sol3/papers.cfm?abstract_id=238193
As Winkler concludes in his paper, "...it remains an open question whether early electoral reforms still serve to protect voters from confusion." I would state it more strongly as parties-in-government manipulation, Winker says, "Minor parties have become occasional spectacles instead of vibrant competitors, campaigns are candidate-centered (as opposed to issues), voters have diminished party loyalty, and the presidential nominating system is skewed so that races are effectively over after only a handful of states have held their primaries or caucuses." Italics inserted.
Because voter loyalty is so ephemeral, the parties-in-government have sought to lock in "their" voters with regulations to suppress defections to competing parties and force dissenters into non-voting. The principle right of voters today is to put up or shut up.
Winkler correctly points out that "Resolving these issues may require a reconceptualization of the right to vote and of the nature of party associational rights similar in spirit and ambition to that of reformers at the turn of the last century."
Spirit and ambition, Reconceptualization not a recapitulation. Before proceeding further it would be best to download and study Winkler's paper.
Citation: Winkler, Adam, "Voters' Rights and Parties' Wrongs: Early Political Party Regulation in the State Courts, 1886-1915" . Columbia Law Review, Vol. 100, No. 3, April 2000 Available at SSRN: http://ssrn.com/abstract=238193