If you study the history of how the big east coast cities have counted votes since the 1840s, the Democrats and other party bosses have always been engaged in electioneering and vote-rigging.
It’s a fascinating history and it was never cleaned up. It’s literally the status quo, and was only solidified when the Mafia bought-off government in the 1920s during Prohibition, then put loyal family friends in Congress and the Courts since that time.
Dixie Mafia was big too. Look at LBJ. There were no “good ol days”.
Organized crime further institutionalized voter fraud and election-rigging, as did the monopolists and kleptocrats. Foreigners were always involved as well, since the old European powers recognized the US as the future. For anyone that was in doubt, the US surpassed all other economies between 1880-1895, and never looked in the rear-view mirror afterwards.
The Brits worked hard to try to maintain as much influence over the ongoings of US Government, but the competition for control is fierce with all the other players.
But yeah, the Democrat party has been running rigged elections for the better part of the last 180 years. They couldn’t win otherwise, and fundamentally knew this all along.