In SecurityCouncilNomineeElectionGovernor, once nominees are excluded from the election by the nominee vetter using excludeNominee(), they cannot be added back using the includeNominee().
This is because excluded nominees are not removed from the array of nominees, but are simply marked as excluded in the isExcluded mapping:
SecurityCouncilNomineeElectionGovernor.sol#L279-L280
Therefore, following check in includeNominee() will still fail when it is called for excluded nominees:
SecurityCouncilNomineeElectionGovernor.sol#L296-L298
This could become a problem if the nominee vetter accidentally calls excludeNominee() on the wrong nominee, or if there is some other legitimate reason a previously excluded nominee needs to be added back to the election.
