Could one hacker alter an entire election?

The more cunning agent who wants to throw the election surreptitiously will modify the votes more subtly in order to avoid tipping his game. It is important not to raise undo suspicion and not to trigger a recount. In order not to trigger a recount or attract a challenge, the changed vote totals must result in an overwhelming victory. The agent can not chance a close election. And while the agent is at it, why not go for a big popular vote margin countrywide. This is best done by narrowing the margins in overwhelmingly blue states and increasing the margins in overwhelmingly red states. For example the difference in NY between actual results and exit poll data is close to 600,000 votes. A few modifications like that and you quickly win a big margin of the popular vote as well as secure the Electoral College.

With the sole exception of Nevada, the nation’s e-vote machines have no voter verifiable paper so recounts are thought to be meaningless. If the agent has modified results in the tally database, an e-vote recount may not be meaningless. But the cunning agent can modify votes in tally machines counting optical scan ballots safely so long as a recount is never done. Thus those five counties in Florida where all the registered Democrats like to vote Republican using optical scan ballots needn’t worry about discovery during a recount because there will never be a recount for those counties.