This seems to fit Trump's evidently prepared-ahead-of-time reaction to Iowa. {movie clip here)
There was an interesting video on Free Republic with a computer programmer testifying before a Panel or Court about a program he was paid to create to ensure a certain candidate in Florida (think the candidate was named Feeney) win an election. The computer expert thought he was doing it to prevent voter fraud, and was stunned it was to ensure voter fraud. He said it is simple to do, but detecting it is much harder. It was asked if this would only affect certain tampered voting machines, but he said all the voting machines would react in unison to the one program.