http://www.nytimes.com/2007/09/17/business/17greenspan.html (greenspans take on Bush's policy)
When many of us criticize Bush's tax cuts, what we generally mean is that Bush's tax cuts were backloaded and contributed very little to the recovery after the Tech bubble. For example, Bush opposed the Democratic proposal to give tax rebates as a way to stimulate demand. One can argue whether or not those rebates had much stimulative effect, but it's hard to argue that Bush's tax cuts had much effect because we were pretty well past the NBER dating of the recession before those tax cuts kicked in.
The fact that most of the investment boom came in the form of a housing boom effectively means that most of our investment is also in the nontradeable goods sector, which is the problem that has COME HOME TO ROOST. More aggressive investment tax credits in manufacturing and education/training was something that Bush didn't really push. In fact, Republicans were actually wanting to make investment tax credits permanent, which would have completely defeated the purpose of investment tax credits because it would not have accelerated the timing of the investments.
Finally, whenever Bush opponents pointed out that a $1 increase in spending had more fiscal punch than a $1 reduction in taxes, Bush frequently replied that he was not tailoring his tax cuts as short term fiscal pump priming. So in this sense Bush was no more than an accidental Keyensian and I think it's a bit odd of the Administration to want to claim credit for being wise Keynesians when at the time they went to great efforts to pooh-pooh pump priming.
777, here's a good read on the situation and what caused it.
http://hnn.us/articles/41985.html
"Our questions should then be, why did this huge investment in subprime mortgages take place, and why should dismal forecasts on the housing/mortgage market affect all others? The short answer to the first question is George W. Bush’s tax cuts—and this answer should give the Democratic candidates another reason to repeal them.
The rationale for these cuts came from the supply-side arguments of the 1980s (personified by Dick Cheney). It goes like this. Investment, productivity, and employment will increase if you augment the incomes of those who do the saving and investing. These already wealthy folks will acquire a new monetary incentive to invest in goods production if you raise their disposable incomes by cutting their taxes. That investment will in turn produce larger payrolls and more taxable incomes, thus canceling the revenue-reducing effect of the original tax cuts."