"To put the blame for all federal spending at Bush's feet ignores the 535 members of Congress who are all after their own piece of the pie."
Of course they all share some responsibility. But only one of the 536 people you mention has the ability to singlehandedly approve or veto a particular spending bill.
My understanding is that, more than ever, spending bills are not single issue/topic spending and designed to aviod a veto (especially with there being no line item veto). Bush is definitely not one to be negative, but the most appropriate place to put pressure is on Congress.