As state secretary of the SDA, Bullock wielded considerable power in the WA branch of the Labor Party. He was influential in blocking Labor support of Sunday trading in WA, which the SDA opposes. He also unsuccessfully opposed changing Labor's policy to support same-sex marriage. Bullock ran for the state Legislative Assembly at the 1994 Helena by-election, caused by the resignation of former Labor minister Gordon Hill. The Labor Party suffered a negative swing of 2.3 points, which was enough to cost them the seat. Richard Court's Liberal government became the first state government since 1943 to increase their majority at a by-election. In the lead-up to the 2013 Australian federal election Bullock reportedly secured a deal with the secretary of United Voice, Dave Kelly, whereby Bullock would take the number one position from left-aligned Senator Louise Pratt in exchange for Kelly's choice of Sue Lines to fill the Senate seat vacated by Chris Evans. Bullock was elected to the Senate as the lead candidate on Labor's ticket in Western Australia, but in February 2014 the High Court of Australia ruled the election void. A special election to elect Western Australia's senators was held on 5 April 2014, with Bullock again being elected. His term commenced on 1 July 2014. On 1 March 2016, Bullock announced that he was resigning from the Senate after less than two years in the parliament. He cited the Labor Party's policy to bind parliamentary members to voting to support same-sex marriage after 2019, among other reasons, for his resignation. Bullock tendered his resignation to Senate President Stephen Parry on 13 April 2016.
Controversy
The Labor member for Perth Alannah MacTiernan criticised Bullock for the power which he and other union secretaries wielded within the party, at the expense of ordinary members and union delegates. The former Labor member for Bassendean, Martin Whitely was also critical of Bullock for allegedly turning his back on a "welcome to country" ceremony, as well as his undue influence within the party, saying in Parliament "I frankly do not believe that Joe Bullock does much that is motivated by the interests of his members; I think Joe does what is in Joe's best interests". Whitely quit the Labor party in 2013 in protest over Bullock's pre-selection for the federal Senate election that year. During the campaign for the 2014 WA Senate election, details of Bullock's speech given at a function in November 2013 were made public. In the speech, Bullock criticised fellow senate candidate Louise Pratt and described some members of the Labor Party as "untrustworthy" and "mad." Bullock issued an apology before the election. Bullock was blamed by figures from Labor's left faction for the party's poor showing in the Senate re-vote. United Voice, a left-wing union, called for Bullock to resign his Senate place. Alannah MacTiernan accused Bullock of costing the party votes. "There are booths that six months ago we were leading and now we're coming third," she said. "We need people who can sell the message; we need to make sure we have people capable of inspiring people." Former Senator Chris Evans said "there's no question that the Labor Party has a serious problem with its preselection processes, particularly in Western Australia." Pratt issued a statement saying: "It is a blow to progressive voters that I would be replaced in the Senate by someone who I have known for many years to be deeply homophobic, to be anti-choice and, has recently emerged, disloyal to the very party he has been elected to represent. Far from my views on these issues being fringe as he has claimed, it is Joe Bullock and other members of the SDA leadership who are on the fringe of mainstream views."
