I’m not talking about how they campaign, I am talking about how they govern. The parties talk different talks, but they walk a very similar walk.
Are you talking about Presidents or Congress? I can't imagine that anyone would think the Bush Admin. and the clintoon admin. were anything alike. I haven't liked everything Bush has done, but I could list an awful lot of differences between those admins - foreign policy, taxes, and nanny state programs being three key ones.
As for Congress, both parties are far too fond of earmarks (and the voters in both parties reward them for it), and both parties are castigated by the voters if they work with a President of the opposite party (the voters demand that they don't)
In short, I don't see the similarities in the Executive branch, and it seems to me that Congress is doing what they've been elected to do. If voters didn't like it, the earmark champions would be defeated and so would the ones who didn't try to work with the President. But those are the ones who win re-election repeatedly.