The Republicans will have to eventually run another candidate in the presidential election than Donald Trump. The questions is supposed to be about whether the Republicans will move away from Trump or if they will continue on a similar track.
The question will be resolved right after the 2028 election to make the question based on the communication during campaigning for the next election.
In case the candidate has changed their mind on the issue, it is the latest stated opinion on election night that counts. If I feel that they are playing both sides I will resolve to vague.
If Ron DeSantis had been the nominee in 2024 I would have likely resolved the question to Vague if he had continued talking like in the following interview: https://www.youtube.com/watch?v=-l2q7zzPB5Q.
While he does say that Trump lost, he clarifies that "Whoever puts their hand on the bible on january 20 is the winner". And he speaks at length about what he believes to be problems with the 2020 election.
In case Trump is the nominee 2028 or there is no democractic election in 2028 then the question will not resolve until there is a democractic election where Trump is not one of the nominees.