I'd say voting for the person that most closely aligns with your positions is not being a petulant child. Voting against somebody is closer to it, but decent short-term strategy. Let's put this problem of ultra-conservative justices where it really lies, at Earl Warren's feet. Without a massively powerful, activist Supreme Court, it wouldn't be that big of a deal to have conservative or liberal justices. Now, things get really complicated. When people have their guy in whatever office, they want that office to do what they want and grow their power. We've seen the legislature get weaker and the executive and judicial branches get much much stronger since the country was formed.
There are many, many more people in the legislature and it being more granular is a better representation of the people than the one or 7 members of the other branches. How did the legislature get so weak? I think it's because of people voting against the other guy instead of voting with the person that most closely aligns with their beliefs. We fall in to a two party system that naturally divides the population in half. That is it's either this guy or the guy most likely to beat this guy. The parties will always teeter around that equilibrium. People only want to give up as much as they have to to get what they want and by this process the 2 parties will always seek towards a 50/50 split of the voters.
I think everybody has a threshold for how many votes a candidate is likely to receive before voting for them. Anything less than that is throwing the vote away. When you disparage 3rd party voters, you lower the number of votes that go to 3rd party candidates and raise the number of votes for the two party system. This is then fed back in to the system so next time an election comes around it's evidence that nobody votes for 3rd parties.
So how do we get out of this? There are lots of complicated systemic ways to address the problem, but the most direct way is to support a legislature that will reign in the executive and judicial branches to lessen the sting of losing the monolithic executive branch to the guy you don't like, then start voting for the person in your legislature that you think will do the best job. This will destroy the two party system and provide more choices. Actually, I think these things are the same thing, just there is a two step process we need to go through. Step one is get the government back under control, step two is use the government to achieve progress. Actually, there is a third step too. Think long term and don't opt for the quick progress that weakens the whole system.