The space race has a very valuable lesson to teach us about fear in space programs.
The reason we still do not have a moon base is because the 1970's space programs where based on fear. I feel the only reason the nation cared about NASA during this time was to beat Russia. During the cold war, we wanted to wipe the communists all over the floor in every, single, possible area. I feel the nation didn't have a passion for space during that time, they had a fear of a communist controlled outerspace. I want to point something out to you, look at this, note the times the NASA budget was more then 1% of the federal budget, then come back.
1962 was the Cuban Missile Crisis, the height and beginning of the mass fear of the cold war. After this point, the arms build up and threat of a nuclear war only increased. 1977 was two years after the end of the Vietnam War, which, in my opinion, was the point where American citizens just got sick of the Cold War. After we we got sick of fear, the motivation for a space program was gone. Plus, we had already "defeated" Russia in the space race, so there was nothing to fear. We "owned" space. So, NASA got it's funding cut. Today, the thing America fears (terrorism) is not in space, yet. So there is even less reason to fund NASA if you used only fear to justify a space program.
Fear also has another problem. If you where to make a graph of public support of a program based on fear it will be similar to Y = (1/X), ignoring the negative X part. Basically, the program will start off with a ton of support, then it will wane off. This is an inefficient support system for a program with long term goals. This is why we can't use fear to support a space habitation program, it will have alot of support at first, but then it will wane off. I feel that a fear based space habitation program will only lead to a single space colony supporting just enough people to have genetic diversity in lower Earth orbit. That is enough to eliminate the fear of human extinction.
In order to move to other stars, the public support for space habitation should look like the graph of Y = 2^X. It should start with very little support, but then increase exponentially until the idea is engrained into the cultural of humanity. Fear does not do this, it only rides the wave of fear until it finds a new idea to power.
