The fourth committee, the Committee of Elections and Qualifications (renamed the Committee of Disputed Returns and Qualifications in 1903), considered the eligibility of senators, Senate vacancies and disputed elections. Electoral legislation adopted by the Parliament in 1902–07 removed many of these functions to the High Court, sitting as the Court of Disputed Returns. The Committee of Disputed Returns and Qualifications was abolished in 1987.

The last matter dealt with by the Committee of Disputed Returns and Qualifications was the appointment of Senator James O’Loghlin by the South Australian Parliament in 1907. O’Loghlin had been appointed to a Senate vacancy after the Court of Disputed Returns found the 1906 election of Joseph Vardon had been invalid. Vardon argued successfully to the committee and the court that O’Loghlin’s appointment was void as the vacancy should have been filled by poll. While O’Loghlin was defeated at the ensuing election, he re-entered the Senate in 1913, later achieving prominence as the only senator to enlist for overseas service in World War I.

In 2017 and 2018, ten senators were disqualified under section 44 of the Constitution. In those cases the court relied on principles established in Vardon v O’Loghlin for filling vacancies resulting from disqualified senators.

National Library of Australia,
nla.obj-136690044

Senator James Vincent O’Loghlin, Senator for South Australia, 1907, 1913–20, 1923–25

National Library of Australia,
nla.obj-136690044

National Library of Australia,
nla.obj-136728052

Senator Edward Charles Vardon,
Senator for South Australia, 1921–22

National Library of Australia,
nla.obj-136728052