Life. That's the starting point, i.e.
after life had originated. It's the same way that the theory of gravity has the starting point of matter. It doesn't explain how matter first originated, it simply explains how matter behaves when it exists.
All scientific theories have specific limits, and it's absurd to ask them to explain phenonema outside of their scope.
That said, many evolutionists think that the separate study of abiogenesis holds some promise.
ID is like saying "God did it" and it primarily uses God-of-the-gaps reasoning to justify itself. It is itself untestable, so it can survive only as a parasite on real scientific and testable theories, primarily the ToE, using designer-of-the-gaps wherever knowledge is currently found lacking. Keep in mind that scientific theories doesn't make us omniscient, and all theories consequently have gaps.
ID is also a piece of propaganda invented to get religion into science class, applying less obviously religious terms to the same old tired creationist arguments to make them appear scientific to the layman.
Peter