In some primary elections, it is possible to vote in only one party's election. My goal is two-fold: remove one party's incumbent candidate from office, and get the other party's best candidate into office. In other words, I am as interested in voting "against the incumbent" as I am "for the challenger".

Given the above, does it ever make sense to vote against the incumbent in his party's primary, by voting for a same-party challenger? Or should I always vote for my preferred winner in her own primary? Are there any conditions that affect which option makes more sense?

I am interested in seeing some mathematical analysis of these options, although I realize it may depend more on psychology or other less rigorous information.


3 Answers 3


It depends on the situation.

In a region where one party is clearly going to win, the Primary is unofficially the general (i.e. In my home state, it is best to Register Democrat because they (usually) always win and the primary is closed.).

Other people will vote for Party A to vote in their primary for the weaker candidate as they want to give Party B's candidate the better shot.

Your situation is closely mirrored to either the above or the below:

You do not care which Party gets the job, so long as the incumbent Candidate is not on the ticket. Here it is to your benefit to register for the Incumbent's Party and vote against him twice.

There are also independents who like both candidates equally (or hate them equally) and want to see the best of both parties before making a decision, which means they will not participate in either primary. This is probably the weakest as they cannot influence the more dominant party, but some voters are principled in their non-committed party lines voting.

Though rare, there are states with open primaries where all voting members can vote for any party they choose without registration (a member registered to Party A can vote on Party B's primary instead... as can an independent) and some where you can vote on both parties (probably the fairest as it is picking your two favorites).

In the United States system, your political party really only matters to the public once you decide to run for an office. While it is never illegal to change parties, America tends to abhor a flip-flop more than an open minded person who realized he no longer agrees with the party line. (Most losing presidential candidates in my life time were seen as the one who's exact beliefs were harder to pin down.). So you can bounce between parties as much as you want in the United States until you decide to run for office... than you better be prepared to part with the party only on pain of death or (worse of an elected official) future political career.

  • I mean to ask about the second case, giving the different-party challenger a better shot. In that case, is there anything we can say about which option is more effective?
    – monguin
    Commented Feb 20, 2018 at 22:49
  • 1
    @monguin: I would say the one risk to voting for the weaker candidate so your guy in the opposition party has an easier challenge is that you might accidentally put the idiot in office. The Democrats encouraged votes for Trump in the Primary as he was definitely the weakest candidate to go against their party front runners. I'm not sure they would have done so if they could see the future. On the other side, Roy Moore was the gift that kept on giving in the Alabama Senator elections.
    – hszmv
    Commented Feb 21, 2018 at 14:35

In 1968, people voted for candidates other than Lyndon Johnson in the early Democratic primaries. As a result, Johnson did not run, therefore guaranteeing that Johnson would not win the election. If your only goal was keeping Johnson out, voting against him in the Democratic primary was a more reliable method than voting for someone in the Republican primary.

It would be possible for a primary challenger to win at the convention. That almost happened with Ronald Reagan versus Gerald Ford in 1976.

In general, it makes sense to vote in the primary where your vote would have more impact. Of course, prior to the election that might be difficult to determine. But with perfect hindsight, voting against Johnson and Ford in the primaries was more effective than voting for anyone in the other party.

This of course assumes that the leading challenger in the primary is acceptable to you. If you dislike Reagan more than you dislike Ford, voting for Reagan is silly.

There are also situations where voting in the challenging party primary is superior. For example, in 1992, Pat Buchanan never had a real chance against George H. W. Bush. Meanwhile, Bill Clinton would eventually be the Democratic nominee and beat Bush.

I'm ignoring getting your challenger in office and only trying to keep the incumbent out. It is of course possible that your challenger would have had a better chance against the incumbent than a new face from the same party. And of course, your preferred challenger might not win that party's nomination.

  • I wouldn't say voting for Reagan is silly necessarily (sans the hindsight). Depends on what the goal of your voting is. Maximizing chances the democrat wins can give a different strategy than minimizing the chance that Reagan wins. If you think the Democrat is more likely to win against Reagan than Ford, and you want to optimize his chances to win, you vote Reagan in the primaries. But if you want to minimize the chances Reagan wins only (not caring about who actually does otherwise), you are likely to vote Ford (depends on how the Democrat potentials match up). Commented Feb 21, 2018 at 19:00
  • @zibadawatimmy And I still say that would have been silly, as we know for a fact (with hindsight) that Reagan was capable of beating Carter. We can't know absolutely that Reagan would have won in 1976, but we do know that Ford didn't. I would also point you at the 2016 Republican primary. Many Democrats trash talked Trump in a way that endeared him to Republican primary voters, raising his profile. That didn't produce an electoral college win for their candidate. It now has them talking nostalgically about George W. Bush.
    – Brythan
    Commented Feb 21, 2018 at 19:13
  • I said sans the hindsight. And capable is not the same thing as guaranteed. A 50.1% chance that Carter bests Reagan, or 49.9% he beats Ford, is still at least a 49.9% chance that he loses either way, but he's still statistically better off against Reagan. As I said, depends on what you're optimizing: X's chances to win, or Y's chances to lose. They're not necessarily the same thing. Commented Feb 21, 2018 at 21:30

In the USA (since country is not tagged/specified at this time) The intention of the political primary election system is to allow a political party to gage how popular a candidate is out of a set. As to how successful it is at doing that, well..... that's debatable.

While voting for the oppose to an incumbents position would seem to "cancel" a vote for the incumbent, it won't truly reflect the popularity of the voting public.

Your vote is your own, but to work within the system you should vote for the candidate you feel best fits the role that the election seeks to fill.

This answer is USA specific.

  • That makes sense, but it's not clear to me whether that answers the question of which is more effective.
    – monguin
    Commented Feb 20, 2018 at 22:49
  • 1
    In theory, the effectiveness is identical either way. In practice, it is rarely so, with the political demographic of the domain in question determining which is the more effective maneuver.
    – GOATNine
    Commented Feb 21, 2018 at 15:11

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .