and delivered a Budget featuring cuts to company tax. However, the elections of July 2016 saw the government returned with a majority on only one and a minority in the Senate, making it more difficult to secure the passage of government legislation. Following a national postal plebiscite, the government legalised same-sex marriage in December 2017. In foreign affairs, Australia signed a refugee exchange deal with the US in September 2016, allowing those in detention on Manus Island and Nauru to be settled in the US. There was increased tension with China because of Australia's criticism of China's policies in the South China Sea, Australia's new laws targeting foreign influence in domestic politics, and a ban, on national security grounds, on Chinese companies supplying Australia's 5G communications network. Trade with China, however, continued to grow. In 2017, the United States, Japan, India and Australia agreed to revive the Quadrilateral Security Dialogue in order to counter Chinese ambitions in the South China Sea. Australia signed a modified Trans-Pacific Partnership trade agreement with 10 other nations in March 2018 after the US withdrew from the original agreement. The government lost five by-elections in July 2018. When, in August, the government sought to introduce legislation for a National Energy Guarantee, including a commitment to meet Australia's emissions target under the Paris Agreement, a number of Coalition members vowed to vote against the bill. The resulting controversy further harmed the government, which had already lost more than 30 consecutive Newspolls. The parliamentary Liberal Party elected Scott Morrison as its new leader and he was sworn in as Prime Minister. Morrison Government (2018–2022) The Morrison government committed to remaining in the Paris Agreement, but promised a greater focus on reduction of energy prices. In foreign affairs the government signed the Indonesia–Australia Comprehensive Economic Partnership Agreement (IA-CEPA) in March 2019. In April, the treasurer delivered a Budget focusing on tax cuts, increased spending on roads and other infrastructure, and a forecast return to a surplus. The government was returned at the elections of May 2019 with a three-seat majority. In 2017, a constitutional convention of 250 Aboriginal and Torres Strait Islander delegates had issued the Uluru Statement from the Heart, calling for the recognition of Indigenous sovereignty, a Makarrata (truth telling and agreement-making) Commission, constitutional recognition of Indigenous Australians and a "voice to parliament". In 2019, the government announced a process to "develop options for a model