More likely that “special emergency” will be thermonuclear attacks on Israel and on US interests in the ME, by Iran and/or Pakistan. Then, 2A suspended, emergency declared, Wall St meltdown, Obama to the rescue, too busy for election.
Remember they suspended the last campaign when the stock market melted down. It does not take much of an excuse.
Keep in mind the reovations to the White House that are- basically- an underground bunker. Someone planning to dig in and be unreachable when a rebellion breaks out? Hitler did it- most dictators set up protection before they declare themselves potentates.
The big question is-what will the military obey, a dictator or the Constitution?