ما هو الحكم الشرعي للشخص الذي يأكل من الولائم التي يقيمها مرشح لمنصب حكومي؟

This type of feast is called a banquet, and it is permissible, with no harm in attending it and eating from it, as long as it is not accompanied by anything prohibited. If the food is free from reasons for prohibition, then the invitee may attend. The host's desire to run for office does not change the ruling if he is qualified for the position and there is no religious impediment to him assuming it.