Which parties have had control of the White House?
Which parties have had control of the Congress?
Legislative and Executive branches have been controlled by two parties the entire time science is studying the problem.
Which party is to blame? Both.
What should be done with these two parties? Keep electing the two parties apparently.
The Solution? Well, both parties were elected with at least one moment they controlled it call: exec. & legis. Why isn't it fixed yet? They both had their chances.
So, who is to blame? both parties.
The real solution is too painful for the world (not just Americans) to accept.
It's like the US National Debt. It's going to be painful to fix, but, like the climate, it'll get worse before the real change is mandatory.