Intelligent Design doesn't presuppose God! What it does is make evidence-based arguments that blind random selection is insufficient to explain the full diversity and complexity of life that is observed. "Design" here means "not randomly caused", but no assumptions are made about the identity of the "designer" -- it could be a technological civilization from elsewhere in the galaxy for example. The core technical concept is that random variation has its limits, which can be characterized mathematically, and that certain conditions on a system allow one to deduce that the probability it could have been created by random-mutation-driven evolution is vanishingly small.
Thank God for natural selection!
It's not really a "third possibility;" it's essentially crypto-creationidiocy repackaged in a shiny new box in an attempt to try to sneak creationism into schools under the radar.
Of course, there's still a group of fanatical Young-Earth Creationidiot types that don't particularly like ID, but actually probably even the majority of Creationidiots have managed to finally figure out that Young-Earth Creationidiocy and absolute Biblical literalism is too obviously stupid to try to sell, at least immediately.
As is usual in a lot of scientific threads, I don't think people grasp how incredibly tiny the ID community is among legitmate scientists. (In contrast, the number of legitimate meteorologists and climatologists that question "Global Warming" theory is quite large, it's just that the media doesn't like them.) It's a tiny group who are continuously cited and re-cited. I'm aware that some of them claim not to be particularly religous but their proselytizers and the people buying their books certainly are.
And of evolutionists probably MOST are religious to some degree, with many thousands being churchgoing Christians and of course many thousands of agnostics or atheists; however, you'll look a long time before you find an atheist creationist; if it truly was such an attractive theory there would be some SOMEWHERE.
Actually, it does. When taken to its obvious conclusion, ID presupposes a supernatural "first cause." Think about it: If the Intelligent Designers were, oh say, little green men from Zeton, how did they come to be? Who were their designers? Who designed the designers? Ad infinitum. ID cannot escape such a supernatural conclusion, and as the supernatural is, by definition, not science (which only deals in the natural), ID cannot be scientific.
In a story told by Stephen Hawking, scientist was giving a lecture on astronomy. After the lecture, an elderly lady came up and told the scientist that he had it all wrong.
"The world is really a flat plate supported on the back of a giant tortoise." The scientist asked "And what is the turtle standing on?" To which the lady triumphantly replied: "You're very clever, young man, but it's no use -- it's turtles all the way down."
The notion of ID proposes a greater complexity to explain a lesser one. How does ID propose to explain the greater complexity. It seems to me they would need something akin to, "It's turtles all the way up."