     DECLARE
       "member_id_v" "member"."id"%TYPE;
     BEGIN
+      PERFORM "require_transaction_isolation"();
       FOR "member_id_v" IN
         SELECT "member_id" FROM "direct_voter"
         WHERE "issue_id" = "issue_id_p"

      "weight_v"              INT4;
      "sub_weight_v"          INT4;
    BEGIN
      "weight_v" := 0;
      FOR "issue_delegation_row" IN
        SELECT * FROM "issue_delegation"

  RETURNS TRIGGER
  LANGUAGE 'plpgsql' VOLATILE AS $$
    DECLARE
      "issue_id_v" "issue"."id"%TYPE;
      "issue_row"  "issue"%ROWTYPE;
    BEGIN
      IF TG_OP = 'DELETE' THEN
        "issue_id_v" := OLD."issue_id";
