The Washington Post explains:
Although many backers of intelligent design oppose the biblical account that God created the world in six days, the Christian right is increasingly mobilized, Baylor University scholar Barry G. Hankins said. He noted the recent hiring by the Southern Baptist Theological Seminary of Discovery Institute scholar and prominent intelligent design proponent William A. Dembski. The seminary said the move, along with the creation of a Center for Science and Theology, was central to developing a "comprehensive Christian worldview."
"As the Christian right has success on a variety of issues, it emboldens them to expand their agenda," Hankins said. "When they have losses . . . it gives them fuel for their fire."
To fundamentalist Christians, Fox said, the fight to teach God's role in creation is becoming the essential front in America's culture war. The issue is on the agenda at every meeting of pastors he attends. If evolution's boosters can be forced to back down, he said, the Christian right's agenda will advance. "If you believe God created that baby, it makes it a whole lot harder to get rid of that baby," Fox said. "If you can cause enough doubt on evolution, liberalism will die."
Fundamentalists and conservative evangelicals view pretty much everything political, social, or religious through the lens of their "culture wars." They are the persecuted church which gospel texts have Jesus predicting and teaching about. They may control most of the levers of political power around the nation, but they have failed to capture enough hearts and minds in order to mold American culture according to their desires. There must be a reason for this and the most common "solution" is that the forces of Satan continue to have the upper hand.
PZ Myers comments on the above story:
This article, though, shows them to be lunatics who are jumping on the superstition bandwagon and riding it to victory. These are people advocating the destruction of good science in order to achieve a political advantage.
I don't know about that — Myers makes it seem as though the conservatives who are the prime movers behind ID don't really believe it but are just using it to gain political advantage. I suppose this may be true about some, but to be honest I think that most firm ID supporters also completely believe it (or a more fundamentalist version of creationism). They believe it because their religion commits them to adopt nonsense if that nonsense is in accord with the Bible. They also believe that if such nonsense is given enough backing and time, more people will adopt it, the culture will change, America will become more Christian (as they define the concept), and liberalism will die off as a sustainable, viable political option.
These beliefs are certainly all connected by their background religious ideology, but they are also distinct in the sense that one doesn't compel the other. It's certainly not the case (generally speaking) that one is adopted simply in order to advance the other.