Cause and effect
If Donald Trump wins the election, the system is not rigged.
If Joe Biden wins the election, it was rigged.
If everyone voted by machines, and Trump lost, the machines were rigged.
If voting by mail and Trump lost, there was fraud.
Only if Trump wins is there no fraud and no rigging.
Did President George H.W. Bush or Hillary Clinton say the system was rigged when they lost?
Hillary won the popular vote, but that was rigged, says Trump.