The AGW crowd kept the lie alive long enough that the president believes in global warming, as does almost every democrat lawmaker, and about half the republican lawmakers, and most of the college professors, and maybe half of the scientists that provide science news...
Actually, there is a case to be made that the AGW conspiracy is ongoing and pretty sucessful.
AGW is believed not so much because the lies were effective, but because those who believe it want to believe it.
It’s called confirmation bias, and its something all humans are subject to. Even conservatives will jump on a “fact” that confirms something they want to believe. Some stories are just too good to check.
I freely admit that I have succumbed myself more than a few times.