The neoconservative era arguably began on September 11, 2001, though its roots go back to the Reagan era. The 9/11 attacks gave president George W. Bush and his party unprecedented political support, and thus the freedom to set in motion an unusually large portion of their political agenda.
As neoconservative propaganda began to take hold in popular belief, an shift in ideological polarization took place in which those who identified with liberalism and progressivism – more or less the polar opposites of neoconservatism – effectively retreated to a position of defending their views largely on rational grounds, in the face of the neoconservative devotion to promoting evidence-free "facts". Neoconservatives, for their part, were actively disdainful of evidence and facts, disparaging those who use them as the "reality-based community".
While there are signs that the shaky foundation of counterfactualism upon which the neoconservatives built their ideological empire – which eventually came to include, at one time or another, the religious right and marketism – the jury is still out on what will happen next. The 2016 elections seem likely to give a good indication of whether public sentiment has shifted significantly.