This is not a review of the movie, it is an analysis of the hidden messages in the movie, and whether it is mainly conservative or liberal. So there will be spoilers below. And by the way, I don't think that the bias in the message is severe enough to spoil the movie for anyone. I barely noticed it at the time.
On the face of it, we have America unable to feed itself, with the return of giant dust storms like the 1930's. But more than just America, in the movie "Interstellar", the entire world is in the same state of environmental decline, and humans will not be able to survive another generation.
This could be a liberal message because Liberals believe in global warming, and apparently, conservatives don't. But actually, I think it is made clear in the movie that this destruction of the Earth is caused by blight or diseases ruining the crops. If you are a die-hard Conservative, you can then assume that dead crops may be causing these dust storms, and not global warming. However, this argument can be taken either way. For example the severity of the Mountain Pine Beetle's recent destructiveness may be linked to climate change.
http://en.wikipedia.org/wiki/Mountain_pine_beetle
I hope I'm not misrepresenting the conservative point of view, but I think the Conservative point of view is sometimes stated like this: "we do not need to be careful of the environment, because human ingenuity will find a way to save us no matter how much destruction we cause."
I will put a quote and a link here to a conservative website doing a similar political analysis of this movie:
"there isn’t the slightest doubt that Nolan’s view of climate change is that it is simply another of the many environmental situations that man is equipped to cope with. In the context of the film, this means extreme actions that make for cinematically exciting scenes, but on an allegorical level Nolan is saying, “Mankind has the creativity to respond to crises, even global ones."
http://pjmedia.com/lifestyle/2014/11/07/5-conservative-themes-hidden-in-interstellar/4/
Is it truly a conservative viewpoint, that if the Earth is failing, we do not need to save the whole planet, we simply need save Humans, probably by getting us off planet Earth? And is it truly a liberal attitude that we need to preserve our planet because we believe that Humans are just evolved monkeys and therefore we are not smart enough to invent a way to survive? If so, then this movie's hidden message really is conservative. Because in the movie, mankind does discover two ways to survive beyond planet Earth. At the end we see these giant spaceships, complete with farms, where people are living with no need for planet Earth. And the movie also presents the possibility of colonizing one of the planets on the other side of the worm hole.
As a liberal watching the movie, I admit that I was simply not convinced that either of these survival plans was really possible. I guess if I was a conservative, I may look at the movie thinking those survival strategies are reasonable, and that the destruction of the Earth is the really unlikely scenario. But it's the ending of the movie that points to the hidden message being truly conservative. Those huge orbiting space colonies are the result of the scientific work by Murphy, solving the riddle of gravity, and thereby allowing humans to build these giant structures and lift them off the earth without much trouble. But as far as I'm concerned, overcoming gravity is no more likely than black magic or holy miracles at this time.
Then, in case gravity was not defeated, "plan B", was to fly through a worm hole to another habitable planet. But Plan B would not allow any more than a handful of existing humans to survive. Those handful of humans that take this trip could take human genetic material to the new planet, and so regenerate the human race again, similar to Noah and the Ark. Again, I am not aware of any theories that humans, or anything, really could get through a worm hole if they really exist. So I think both Plan A and Plan B are just cop outs without any real scientific basis.
So we come back to planet Earth, and the big question: is it worth preserving or should we simply exploit our planet to the maximum then bug out? What I find strangest is that preserving the Earth has become a Liberal point of view in recent years, while developing technology to escape the Earth used to be the Liberal point of view. In the past, Conservatives were really all about "conserving" and liberals were all about scientific discoveries (such as evolution, DNA, nuclear physics, and the Earth is not flat). Ironically, the people most intent on self destructing planet Earth today are not the scientists, they are the religious nuts who believe the end of times are at hand, and their political allies, the Conservatives. But the theoretical scientists are the ones who have the best chance of inventing the technology needed to save us, and they are mostly liberal, working outside the corporate culture of short term profitability.