You can't have elections when you're being invaded or under attack, it's not unprecedented and it's also constitutional. The UK for example didn't have elections from 1939 to 1945 due to WW2.

If part of your population is under occupation, they won't be able to vote how they want, and the rest of your civilian population becomes a target for constant bombardment in order to vote "correctly".

The U.S. and the Confederacy held elections during the Civil War, when each was invading the other.

The US is the only western country that doesn't have provisions to suspend elections during wartime. Bully on you, you're awesome. But it doesn't make France, Germany, Canada, the UK, Italy, Spain etc. dictatorships because they don't do exactly what America does.

Ah yes, the Civil War, a famous conflict where attacks behind the frontline were common due to airplanes and ballistic missiles. /s