That's an interesting theoretical attack that I hadn't considered, thank you for sharing it.
I think a possible rule to defend against it would be to mandate that any political party needs to have received at least 5% of the popular vote in that local region in the previous local elections in order to be eligible to stand candidates for the national congress/parliament.
If a candidate wants to stand without the backing of any political party, they would need to receive at least 20% of the (first round) votes in their district in order to win (without needing to stand in the local elections first).
Forcing candidates to publish their vote assignments at registration time might be the way to go, though, as it would help to expose these straw candidates, and also mean that the candidates wouldn't have to be present when the voting result is announced.
To avoid embarrassment, candidates could place a "null" option in their lists, meaning "If I am eliminated, then discard all the votes I received (including the votes assigned to me from earlier-eliminated candidates) and let the remaining candidates win or lose based on the remaining votes".
I think a possible rule to defend against it would be to mandate that any political party needs to have received at least 5% of the popular vote in that local region in the previous local elections in order to be eligible to stand candidates for the national congress/parliament.
If a candidate wants to stand without the backing of any political party, they would need to receive at least 20% of the (first round) votes in their district in order to win (without needing to stand in the local elections first).
Forcing candidates to publish their vote assignments at registration time might be the way to go, though, as it would help to expose these straw candidates, and also mean that the candidates wouldn't have to be present when the voting result is announced.
To avoid embarrassment, candidates could place a "null" option in their lists, meaning "If I am eliminated, then discard all the votes I received (including the votes assigned to me from earlier-eliminated candidates) and let the remaining candidates win or lose based on the remaining votes".