Democrats have been denying and questioning election results for decades when their candidates have lost.
For Democrats, questioning the outcome of the 2020 elections is almost a criminal act, and any reference using the term irregularity, voter fraud, or election theft is immediately censored by the media, violating constitutional free speech rights and demonizing and even sanctioning, and/or imprisoning for the use of the phrases their political opponents, a simple citizen or those who protested in demonstrations. However, from 2000 to 2016, the vast majority of Democratic politicians, including presidents and senior officials, used the same phrases they condemn today and much worse, as the video shows.
Claiming the Republicans stole the election, labeled Bush and Trump as illegitimate presidents, and even had the Supreme Court pick the president, etc, etc, etc.
It's not just the presidential election. Numerous Democrats have falsely claimed that Stacey Abrams won the 2018 Georgia gubernatorial election, including Kamala Harris, Hillary Clinton, Elizabeth Warren, Terry McAuliffe, Cory Booker, Howard Dean, and Eric Holder.
