There is no constitutional provision for Special elections. It would not happen.
True unless Congress passed a limited law for that purpose.
But I doubt they would pass a law that said the ‘runners up’ would get in, I mean let’s get real.
The bottomline is the the country would be faced with a new experience and congress could pass a law to allow special election if the American people demanded it.
Otherwise democrats will just gather around and ‘appoint’ whoever they want. Certainly Pelosi would try and claim her right as Speaker but I think she is so unpopular that dems would force her to step down and then elect another Speaker who would then ascend to become potus. But Americans would be mad as hell.
We had one unelected potus, Ford and he was not reelected. Even though in 1976 the country was in favor generally of a GOP president, they voted Ford out and replaced him with an incompetent, Carter.
If the dems in the house decide to replace Pelosi and thereby elevate a member to potus, I think the American people would be so furious that they would vote out 100+ dems in congress and demand a special election.