The two territories have each been represented by two Senators since the 1975 election, following Whitlam government legislation that survived High Court challenges in 1975 and 1977. Whereas the state Senators serve six-year terms that are fixed but for the possibility of a double dissolution, the territory Senators' terms are tied to the House of Representatives. The formula for election is the same as for the states, but it has very different consequences given that two Senators are elected rather than six. The quota in either case is one divided by the number of seats up for election plus one, so a territory election quota is 33.3% rather than 14.3% at a half-Senate state election, or 7.7% at a double dissolution.
A party is thus guaranteed of a seat if it wins a third of the primary vote, which the major parties have only failed to manage on a small number of occasions in the Northern Territory: the Country Liberal Party on the one occasion they faced opposition from the Nationals in 1987, and Labor by a narrow margin in 2013. Preferences were easily enough to get their candidates over the line on both occasions. Consequently, none of the territory Senate elections has produced a result other than one seat each for Labor and the main Coalition party. The most likely scenarios to disturb this in the Northern Territory would involve one or other major party winning both seats, in effect requiring it to win two-thirds of the two-party preferred vote, which has never looked like happening.
Labor's seat has been held since the 2016 election by Malarndirri McCarthy, who held the seat of Arnhem in the Northern Territory parliament from 2005 until her defeat in 2012. McCarthy came to the seat in succession to one-term member Nova Peris, the former Olympic hockey player and sprinter who was contentiously recruited by Julia Gillard to replace Trish Crossin at the 2013 election. Peris and McCarthy were, respectively, the first and second indigenous women ever to serve in the federal parliament.
In second position on Labor's ticket is Wayne Kurnorth, a United Voice organiser, although he has in fact withdrawn as a Labor candidate after it emerged he had shared anti-Semitic videos on Facebook in 2015, one of which featured popular British conspiracy theorist David Icke's thesis that the world is run by shape-shifting Jewish lizards. Shorten overreached in distancing himself from Kurnorth, asserting he had never met him, a claim belied by a photo of the two that emerged soon after.
The Country Liberal Party's position is to be vacated at the election with the retirement of Nigel Scullion, who has held the seat since 2001 and served as Indigenous Affairs Minister since the Coalition government came to power in 2013. The preselection vote to replace him was held in March and won by Sam McMahon, a Katherine-based veterinarian, who was chosen from a field of 12.