honest broker

one who works with opposing sides in order to bring about an agreement <after all the bad blood on both sides, we need to find someone who hasn't been influenced and can act as an honest broker> Synonyms broker, buffer, conciliator, go-between, mediator, interceder, intercessor, intermediary, intermediate, interposer, middleman, peacemakerRelated Words troubleshooter; moderator; bargainer, negotiant, negotiator; appeaser, pacificator, pacifier, reconciler; agent, attorney, deputy, factor, procurator, proxy; liaison, medium; ambassador, emissary, envoy, legate, messenger; delegate, representative; busybody, interferer, meddler; arbiter, arbitrator, judge, referee, umpire; adviser (also advisor), counselor (or counsellor)