This was the purpose of the Australian Democrats party before they died out.

At a Melbourne media conference on 19 September 1980, in the midst of the 1980 election campaign, Chipp described his party's aim as to "keep the bastards honest"—the "bastards" being the major parties and/or politicians in general. This became a long-lived slogan for the Democrats.

https://en.m.wikipedia.org/wiki/Australian_Democrats