Most voting is about the next election, not this one.
When people vote, what do they think it will accomplish? How does this affect how they vote, and how should it?
My apologies for more of this in a season when our social media are overwhelmed with politics, but in a lot of the postings I see about voting plans, I see different implicit views on just what the purpose of voting is. The main focus will be on the vote for US President.
The vast majority of people will vote in non-contested states. The logic is different in the "swing" states where all the campaign attention is.
In a non-contested state, there is essentially zero chance your vote will affect the result of the election. If you're voting thinking you are exerting your small power to have a say in who wins, you are deluding yourself. Your vote does one, and only one thing -- it changes the popular vote totals that are published and looked at by some people. You will change the total for the nation, your state, and some will even look at the totals in your region.
For minor party candidates, having a higher vote total -- in particular reaching 5% -- can also make a giant difference by giving access to federal campaign funding, which can make a serious difference in the funding level for those parties.
Voters should ask themselves, whose popular vote total do they want to increase? Some logic suggests that it makes more sense to vote for a minor party that you support. Not because they will win, but because you will create a larger proportionate increase in their total. One more vote for a Republican or Democrat will be barely noticed. One more vote for a minor party will also on its own make no difference, but proportionately it may be 10 times or more greater.
It's for the next election, not this one
You don't increase the popular vote totals to affect this election. You do it to affect the next one. Supporting a party makes other supporters realize they are not alone. It makes them just a bit more likely to join the cause, if they believe in it. Most voters don't understand this "next election" principle, and so while a minor party remains too small to win or affect the election, they are less likely to support it.
This is how most movements go from being small to being large. When a protest movement is small, people are afraid to show their support. When they see a real crowd march in the square, they are now more likely to join the crowd and to let the world see how much support there really is.
As such, the particular platform planks and candidate quirks are almost entirely irrelevant for the non-swing voter. When you're voting for the next election, you are really supporting only the party and its broad platform, or a basic overall impression of a candidate. I often see voters say, "I could not vote for a candidate who supports X" but they do not realize that is not what they are doing.
The minor parties are particularly bad at this. Most of them like to pretend they are just like major parties. They nominate candidates based on what they say or stand for. They create detailed party platforms. This is an error. A detailed platform is only a reason for people to vote against you. Detailed platforms are only for candidates who might actually have a shot at implementing their platform. Minor party candidates take it as gospel that they should never admit that they can't win, even though any rational person knows it quite clearly. The reality is that you can know you can't win the current election, but can more reasonably hope you can step higher and get within range of winning in a future election. Only when this happens should you act like a major party. You almost never see minor candidates say the truth: "Vote for me, not because you can make me win -- you can't -- but to show and build support for the ideas of our party."
I personally would much rather vote for somebody who said the truth like that, but perhaps I am unusual.
As I've said earlier, under this philosophy I recommend people in non-swing states consider minor parties that they want to boost. While it is commonly said that voting for a minor party is "throwing away your vote," I believe it's more likely that voting for a major party is actually throwing away the vote. The major party vote will not move any needles, not wake anybody up to the existence of these major parties. Because the minor party can't win, you can vote for it simply to signal that there is support for its core ideas. This is something a voter should consider even when they still prefer the major party more. Most minor parties have bizarre and fringe policies that most voters would not support. Because they can't win, this is not important. Should they ever get bigger, they will moderate those policies, or they will never make the jump to serious contender. Yesterday the John Oliver show did a funny skewering of minor party candidates but it entirely misses this point.
In addition, as minor political movements gain strength, they get noticed by the major parties. If the Greens got 10% of the vote, you can bet the Democrats would take notice, and try to court those voters. They don't want the Greens to get so large that they become a potential "spoiler" in the swing states, so they will become slightly Green to prevent that. Once again, how you vote today affects the election of the future.
Polls are good too
Of course, even better is to express these desires in the polls. What you say in polls can affect this election, but primarily polls encourage other people who think like you to come out of the woodwork and express that view. Polls are stage one in the process of gaining critical mass -- they lead to actual votes, which lead to more polls and so on. Of course, you only want to express support for a party in a poll if you really want this to happen. You should not lie, but you should not be afraid to show what you really support because somebody convinces you it's wasted.
What if everybody voted this way?
Some people have said to me, "If everybody voted for minority views the vote might actually become real!" All remember the 2000 Florida election where Greens split out the Democrat vote and that resulted eventually in President Bush the 2nd. That was a swing state. People knew that would be close.
The truth is, the idea that you are voting for the next election is not widely accepted at present. Perhaps in the future it will be strong enough to change a state from non-contended to swing. But not today.
It's also true that if you leave in a really non-swing state, like California, it is impossible your vote will make a difference. The truth is, if it ever got to the point where California was 50-50 about a choice like Clinton-Trump, then Trump already won long ago in the other states. Solid safe states can't be the deciding state. (Rare events, like having the Republican candidate be a California governor can turn a safe state into a swing state, but not by surprise.) The only way the truly safe states ever can swing is in an election that's already settled. The polls will tell you things long in advance.
Can this really work in the USA?
The biggest counter-argument to this approach I have seen is the suggestion that the USA is different, that the two party system is so entrenched that anything else is a waste of time.
In the rest of the world, 3rd parties are very common. They often are players in elections and often no party gets a majority and so coalitions must be formed, where the large party agrees to do some of the agenda of the smaller party to get their support in the coalition. Parties begin small and grow, as described above. Parties like the Greens are now a powerful minority force in Europe. Some countries, like Iceland, have never had a majority party.
The USA has been two-party for a long time, and the two powerful parties tend to make the rules so as to keep it that way. The above federal funding rule is just one example. In Presidential elections, the system requires a majority in the electoral college. A serious 3rd candidate could simply mean the election is sent to the House of Representatives (which is now long term Republican due to gerrymandering.)
There are some approaches that could cause minority political opinion to be able to do more in the USA. The best would be to move states away from plurality methods to multi-candidate voting such as Approval voting or a Condorcet method. These are no rules against a state doing that for any of their elections. They don't because the two parties like keeping it as two parties. Efforts are underway in the states that have ballot propositions (bypassing the two parties) to make such changes.
What about major parties
This view also can affect your vote for major parties. For example, even though you know your vote in California will make no difference, you may want to make a tiny contribution to public and party perception of how much one party beat another. You may want to support the idea of a landslide or a "mandate." You might also go the other way, and vote to punish your preferred party (for not listening to you or picking the wrong nominee) by voting for the other major party so that they don't think they have a mandate. Sanders supporters who hated Clinton would be foolish to vote for Trump in a swing state, but in the safe states they could send this message if they desired. (It should be noted that this does run a very tiny risk of causing the popular vote to not match the college, which doesn't stop your candidate from winning but sends a very strong message of dissatisfaction, and causes some lessening of support for the legitimacy of the process.)
What about in a swing state
This logic applies much less in swing states. There, your vote might change the state, and there is a very low chance it could swing the election. Now it is worth pointing out that this has never happened in a Presidential election. There's never been an election where one vote made a difference. Unlike the non-contested states, there is still a chance of this happening. There, you will certainly vote for a major party if you want one, and you might even think twice about doing so even if you love a minor party, since your desire to pick the least of the two evils may exceed your desire to show support for your real values. Here, it is possible for minor parties to split the ballot, and in the view of the major parties, "spoil" the vote. This point is valid, the main error is in people applying this advice outside the swing states.
It is an interesting exercise to calculate just how much effect a single vote has even in a swing state. Again, the probability that a single state makes the difference in the election is already low in most elections, and the probability that this state's result is within a single vote is also extremely low. On the other hand, if it does happen, then it happens for every voter in the state who voted for the winner -- they all made the difference equally.
What is it worth to be able to make your candidate become President? In 2012 it was estimated that donors put in $2.6B, and that was not for a guarantee. For an ordinary individual, one could do research to figure out what it's truly worth to each voter by trying to ask how much money they would take to accept the other candidate. That will vary from race to race and person to person, but for most people, it doesn't make a huge difference in their lives who is President. They might feel they will make a bit more money with one, be a bit happier, get more things they care about done, but it's not worth millions to anybody but business people who think it will majorly affect their business. Throwing out ballpark numbers, let's assume it's worth $100,000 to a given individual -- and I think that's actually very high, and of course I know it's not just about money.
The problem is that the odds of the vote actually making the difference are low. Even a close race usually has a margin of thousands of votes, so the odds of a win-by-one are perhaps 1 in 10,000, and the odds that your state will be the decider are also small. After all, only a few elections have ever been decided by one close state, though Florida of 2000 is one of them and it's in recent memory. If you judge your state has a 1 in 100 chance of being the decider, then this back of envelope calculation values your vote at just $1 -- a one in 100,000 chance of something worth $100K.
One might argue that bumping the popular vote total is worth more. Unlike changing the result (which almost never happens) your vote always changes the popular vote totals, no matter which election or state you vote in. So while the value of that is small, the fact that it always happens bumps its expected value. Would adding 100,000 votes to the Green total in California be worth $100K to the Greens there? I would say it would be far more, suggesting a value much more than $1 per vote.
This may explain why voter turnout is so low.