I answered "conservatives" which was probably predictable given that it's me, but I want to clarify that if you had asked by party (Democrats or Republicans) instead of by ideology (liberals or conservatives), I would have said both.
We have been on the wrong track since at least 1981, and in some ways since 1977. But Carter only put part of it in place and half-heartedly (increased military spending, anti-labor attitude). Reagan increased both of those and also flattened the tax system and began the deregulation process. He also gave voice to the economic ideology that ruined us, even though he wasn't personally responsible for all of the damage.
His successors have kept us on the same course. That includes Bill Clinton, not just the two Bushes. So far, Obama hasn't undone the damage, either, or really tried to. So Democrats and Republicans are both to blame. But all of the policies that have hurt us have been conservative policies, even when put in place by a Democrat, as Clinton signed the repeal of Glass-Steagal and pushed through NAFTA and GATT.