"There is no evidence that that (rigging) has happened in the past or that there are instances in which that will happen this time. And so I'd invite Mr Trump to stop whining and go try to make his case to get votes," Obama told reporters at a White House news conference.
Democracy, by definition, he asserted works by consent, not by force.
"I have never seen, in my lifetime or in modern political history, any presidential candidate trying to discredit the elections and the election process before votes have even taken place," Obama said, adding that this is unprecedented.
"Keep in mind, elections are run by state and local officials, which means that there are places like Florida, for example, where you've got a Republican governor, whose Republican appointees are going to running and monitoring a whole bunch of these election sites," he said.
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The notion that somehow if Trump loses Florida, it's because of those people that you have to watch out for, that is both irresponsible, doesn't really show the kind of leadership and toughness that one want out of a president.
"That's OK, you fight through it, you work through it, you try to accomplish your goals. But the larger point I want to emphasize here is that there is no serious person out there who would suggest somehow that you could even rig America's elections, in part, because they are so decentralized and the numbers of votes involved," said the US President.
"It would be my job to welcome Mr Trump, regardless of what he's said about me or my differences with him on my opinions, and escort him over to the Capitol, in which there would be a peaceful transfer of power," Obama said.