Glynn helped found the South Australian Land Nationalisation Society, and served as president of the South Australian branch of the Irish National League. He hosted the 1882 Australian tour of John Redmond, the leader of Irish Home Rulers. In 1887 Glynn's easy personal manners and prominence as an editor assisted him in his election to the
South Australian House of Assembly as the member for
Light. In the chamber Glynn was an unwavering advocate of free trade, but his support of female suffrage and land nationalisation isolated him from his conservative colleagues. Glynn was defeated at the
1890 election and stood unsuccessfully for Light again at the
1893 election but returned to South Australian colonial politics in 1895 as the member for
North Adelaide. With this victory, he became the first person in Australia to be elected under adult suffrage (whereby females had the right to vote). While he was defeated a year later at the
1896 election, he returned to parliament in a
by-election for the seat of North Adelaide in 1897. Glynn briefly served as
Attorney-General of South Australia in 1899 and remained in parliament until 1901.
Constitutional convention Glynn saw no merit in federation itself, but evidently perceived an attractive affinity between the federalisation of the United Kingdom by Home Rule and the creation of a federation of the six Australian colonies. Glynn successfully stood as a candidate for the Convention that framed the
Australian Commonwealth constitution in 1897–98. He was regarded as one of the ablest authorities in Australia on constitutional law. He made major contributions to Murray River water rights, and advocated standardisation of rail gauges and universal suffrage. He also contributed a reference to God in the preamble to the Australian Constitution. He unsuccessfully sought to have the Chief Justices of the Supreme Courts of the states made
ex officio members of the projected High Court. He protested the Constitution licensing the first Governor General to appoint a prime minister and cabinet prior to the first election as "opposed to all our notions of parliamentary government". In the struggle over question of Federation in Western Australia, Glynn with some deviousness secretly drafted a petition, signed by 28,000, which implored the British government to carve out of the goldfields a new colony, 'Auralia'. Such a new colony would not serve Federation but its possibility was judged by Federationist strategists as likely to induce some Western Australians to support joining the new Commonwealth. ==Federal politics==