Post-truth
Nice thead. We are definitely in the Post Truth era. But having said that, I'm referring specifically to the way obvious lies are treated publicly, not individually. In the past (as now) everyone had their personal appreciation of what they understand to be the truth. What has changed is the way what is commonly understood to be the truth (by a majority of society), no longer serves as a guardrail to moderate publicly spoken opinions.
For example, everyone has a preference of how a society should work. Many in the past, collected observations of society, pondered what "worked" and didn't work, then came to a conclusion based on their interpretation of the "evidence". Now many more folks come to (an expedient) conclusion first, then cherry-pick observations to support that conclusion. In the first scenario, new evidence can change the conclusion, in the latter new conflicting evidence is discarded (just as conflicting evidence was discarded initially) so the (usually self serving) conclusion is never changed.
Similarly, in the past public figures feared appearing to have conflicts of interest, or appearing to behave inappropriately and thus often tempered their behavior and their rhetoric to give the (often false) appearance of fairmindedness. Now public figures know that their constituents likely support their policies regardless, that is they and their constituents share the same conclusion of how society should work, so are willing to overlook impropriety, scandals and (for the purposes of this thread) lying.