Years ago I read an essay that argued that every voter ought to isolate the three issues that they feel to be most important and then determine which candidate best fits those issues. The idea of limiting yourself to three issues is that it forces you to prioritize which ones matter the most.
In the interest of full disclosure, here are mine. They all rank about equally for me.
First is the preservation of our rights as established by the US Constitution. Some people favour the First Amendment, some the Second, but I love them all. Any candidate that I support will have to show a working knowledge of the Bill of Rights and some level of commitment to not test their limits.
Second is the elimination or at least radical reduction of earmarks. There is a climate of corruption in Washington these days and neither party and none of the candidates really want to address it. The reason for that apathy is simple. To battle earmarks, they have to fight their colleagues. The logic of Washington is equally simple, the people loathe earmarks and the politicians love them. Currently the politicans are winning on this issue.
Third is space exploration. I am one of those nutty guys who loves science fiction and watched star wars a couple of zillion times. But I also think that of all the things the federal government can do, opening up space for exploration and settlement is the most worthwhile. It would give us back the frontier. We haven't had one for a while and I think we are paying the price for it in the malaise that is affecting the varied worldwide cultures. Thats the metaphysical reason.
The other is that the challenges that are before us currently have no simple solution. For example, if we commit to helping the homeless then we rapidly find that an awful lot of the homeless do not wish to be helped. They are homeless for a reason, be it insanity, drug abuse or alcoholism. And there are no simple solutions to those problems.
If we commit to fight global warming, then we are committing to damning future generations to poverty. Good luck with that one. That's the real reason why no country has actually done anything about global warming.
Space exploration is different. For one thing, if we export our polluting industries to space, there's a really big incinerator down the gravity well from us. Also solar energy, which is generally not practical inside the atmosphere, becomes the optimal energy source in the vacuum of space.
Space exploration and settlement will not be cheap. There are significant technical problems. But the problems that remain are just that, technical. They are solvable.
Those are my three issues. What are yours?