Read the whole article, but the last two paragraphs are especially chilling:
However, the report theorizes that presidential emergency power could be used to delay an election — specifically, if “attacks, disruptions and destruction are so severe and so dangerous in certain localities, particularly in crowded urban areas, that the President under a rule of necessity may look to protect the public safety by federalizing State national guard and restricting movement and activities in such areas which would obviously affect the ability to conduct an election at those sites.”Congress could also theoretically step in and pass a law or give that power to the president, the report says. Courts have typically left it up to Congress to set election procedures.
This would represent a Constitutional crisis since only Congress can change the date of an election. If the president changes the date of the election by executive decree, the consequences will be immediate.