By contrast, the position of a directly elected regional president or governor and of a directly elected mayor may be more comparable to that of a president in a presidential system, to the extent that the incumbent could abuse of his or her office in order to distort the electoral competition and the equality of opportunity of all candidates, and also to concentrate powers to an excessive extent. These risks prevail over the advantages of accountability and competence incentives. The check on their powers exercised by the sub-national or municipal councils might not be sufficient. For this reason, the imposition of term limits on directly elected sub-national or local executive officials could appear more justifiable. Comparative law supports this conclusion.