The fundamental basis of evolution is that present life forms are descended from primitive ancestors and that the process was guided by natural selection. Creationists and Intelligent Design proponents attack evolution by attacking the concept of natural selection. However, even if it could be done, disproving natural selection does not automatically disprove descent with modification. How evolution occurred and whether it occurred are two separate concepts.
If not evolution, then what? Leaders of the ID movement have no scientific answer. They criticize natural selection (and by extension, evolution) for what they perceive as a lack of factual evidence. Yet they don't propose a different model of origins consistent with Intelligent Design.