A simple election reform to encourage moderates to run, and win, would be approval voting, in which voters can “approve of”—and thereby vote for—as many candidates as they like. The candidate with the most “approvals”—votes—wins the election. Because approval voting does not restrict voters to supporting only one candidate, it tends to result in the election of a centrist, not the strongest minority candidate who benefits from a divided field.
Approval voting is widely used by major engineering and scientific societies to elect their officers. At NYU, the politics and economics departments use it to elect a chair.
To implement approval voting in public elections, the parties could choose to use it in their primaries, or state legislatures could mandate its use. Bills to do this have been introduced in several states, including New Hampshire.