Campaign duration limits run into the same free-speech issues that campaign finance limits run into. It's all well and good to restrict what the office holder

Campaign duration limits run into the same free-speech issues that campaign finance limits run into. It's all well and good to restrict what the office holder is doing, but how do you stop "unrelated third parties" from "expressing their genuine political beliefs" without simultaneously stopping real unrelated third parties from actually expressing their genuine political beliefs?