One can express a preference without having the right to participate in the selection.

Quite a few non-US citizens express a preference on who wins the Presidency, for example.

https://www.timesofisrael.com/uks-karim-khan-elected-next-ic...

> Israel’s Kan public broadcaster reported that Israeli officials supported Khan’s candidacy behind the scenes, and consider him a pragmatist who shies away from politicization.