Let's set aside the issue of the scientific evidence for now.
We can't show evidence for ID or creationism in school because it makes reference to a designer, which might be God, and this violates the first amendment.
And we can't show any evidence that might cast doubt on darwinism either, because students might then want to know if there is an alternative, and we would look really stupid saying, "I can't tell you about this, because it would be against the constitution."
Which means that darwinism has to be the only worldview taught as science in schools.
Which means that people who have done high school science will probably think that any alternative is fundamentally not science, and this inference isn't based on a consideration of scientific evidence, but simply on the basis of the constitution.
Now is science supposed to work by studying the evidence? Or by constitutional fiat?
Let's try again, and again set aside the issue of evidence.
We won't teach creationism or ID in science at university because it contradicts philosophical naturalism - the principle that science is only about natural causes. We won't draw attention to the fact that philosophical naturalism isn't the only way of doing science, and is actually a reflection of a particular philosophical worldview - that is, it is a religious or philosophical belief. We won't mention that most of modern science was founded by people who accepted that the scientific method inferred methodological naturalism but not philosophical naturalism.
Which means that students won't be looking at ID or creationism regardless of the nature of the evidence for design.
Which means that the rising generation of scientists will have not investigated the arguments for themselves, and will simply accept the assertion of the older generation that ID and creationism aren't scientific. This isn't on the basis of analysis of the evidence that they present, but because they have been told this is the case - how many undergraduate students really understand anything of the philosophy of science?
Is this how science is supposed to work?
People accuse the ID community of playing politics. There are almost certainly groups within the US that are doing that. But at least part of the reason for this is because the debate has been closed down politically, and not in terms of science. No substantive scientific case is being made against ID and creationism. Instead, their opponents are more concerned to prevent discussion occurring - and will make reference to the constitution, federal judges and philosophy to prevent discussion of the evidence happening.
