Australian Slang for someone unimportant or inconsequential, and somewhat ironically also the nickname for (ex) Australian Prime Minister, Robert James Lee Hawke.
Bob Hawke came about the nickname during his abrupt appointment as leader of the Australian Labor Party in 1983. Prime Minister at the time, Malcolm Fraser called a snap election after a win in a minor by-election by his Liberal Party. The Liberals chances at reelection were low given persistent unemployment, increasing inflation, industrial disputes, and drought, but the byelection had given the party a glimmer of hope.
On the eve of the announcement of the election, the Labor Party strategically dumped its leader Bill Hayden for the more charismatic Hawke, despite already being a shoo-in for toppling the standing Liberal government after 7 years in opposition.
Despite moves against Hayden beginning months earlier, understandably annoyed at his ousting he remarked to the media that "even the drover's dog could lead Labor to victory". The name for Bob Hawke stuck, possibly due to Hayden's apt use of the term.
A "drover's dog" is a working dog used primarily by the drover for driving sheep and cattle to market. It is speculated that these dogs were tax exempt due to their working status. To prove their occupation, their tails were docked, leading to the custom of naming the sheepdog "Bob" or "Bobtail". The docking of tails also lead to the dogs being seen as inconsequential - that despite being necessary for herding in the Outback, drovers would treat their canine companions like a dog with contempt and cruelty.
The slang term "as dry as a drover's dog" is also used to denote that one is extremely thirsty, as the dog in question works all day in the driest parts of the driest continent on earth. Bob Hawke's thirsty nature is without doubt. During his time at Oxford University, he held the world record for chugging a yard glass - a record yet to be matched by popularly elected world leader