A quick look over <a href="http:&#x2F;&#x2F;politicalgraveyard.com&#x2F;offices&#x2F;pdio3.html" rel="nofollow">http:&#x2F;&#x2F;politicalgraveyard.com&#x2F;offices&#x2F;pdio3.html</a> says nobody has died in office in a presidential election year in the last century, so the circumstance is itself unprecedented in modern times.