"The Darwinian mechanism claims the power to transform a single organism
. . . into the full diversity of life that we see both around us and in
the fossil record. If intelligent design is correct, then the Darwinian
mechanism of natural selection and random variation lacks that power"
(Dembski 2001).
The claim is a non sequitur. Intelligent design says nothing at all
about the Darwinian mechanism of evolution. Whether or not evolution
lacks power must be decided by looking at evolution. If intelligent
design is correct, it provides an alternative explanation, but it
does not automatically falsify other alternatives.
The Darwinian mechanism of natural selection is part of the normal
design process. If designers were not able to abandon old designs in
favor of better modified versions of the same design, then intelligent
design would have very little power itself.