I agree with Jay to the extent that Miers' nomination was not some sort of stalking horse. Its fairly obvious that Bush miscalculated the level of support she would need or receive.
Does that mean Bush is doomed for the next three years of his presidency? No.
Does it even mean the next nominee will also go down in flames? No.
It only means that Bush needs to nominate someone who will mend the fences with his base.