3 nightmare election hack scenarios

The question on the mind of many voting security experts is not whether hackers could disrupt a U.S. election. Instead, they wonder how likely an election hack might be and how it might happen.
The good news is a hack that changes the outcome of a U.S. presidential election would be difficult, although not impossible. First of all, there are technology challenges -- more than 20 voting technologies are used across the country, including a half dozen electronic voting machine models and several