There are common threads in the political careers of Jacinda Ardern and Leo Varadkar. He was 38 in June 2017, when he became Ireland’s youngest taoiseach, as well as its first gay and first mixed-race leader. Four months later, Ardern became the world’s youngest female head of government when she was elected, aged 37, as New Zealand’s prime minister. After five and a half years in office, she resigned in January 2023, saying “I know what this job takes. And I know that I no longer have enough in the tank to do it justice.” On Wednesday, after clocking up four and a half years during two separate periods as prime minister, Varadkar announced that he, too, had emptied the tank. Voice quivering, he said: “I am no longer the best person for that job … politicians are human beings. We have our limitations. We give it everything until we can’t any more and then we have to move on.” Ardern stood down in New Zealand with her popularity at record low levels. Access to affordable housing was one of several issues linked to her slide. Nine months later, Labour, under new leadership, was out of power. Ireland’s politicians face local and European elections in June and a general election has to be held by March 2025. With a housing crisis, soaring health budgets, rows over refugee policy and the blame game over recent referendum defeats, Varadkar had reached the conclusion that Fine Gael, under his leadership, was likely to be punished by voters. A World Happiness Report, published on the morning he resigned, placed Ireland in 17th position, down four places since 2022, with Finland ranked No 1. (The data has the UK 20th and the US 23rd). In the 1840s, more than 8 million people lived in Ireland. The famine and subsequent decades of emigration had, by the early 1960s, reduced the population to 4.3 million. Today, for the first time in almost 200 years, the population of the island, north and south, is above 7 million. Successive administrations in Dublin have struggled to deal with the new challenge of a growing population. A generation, including well-educated, two-income couples, can’t get on the housing ladder. Dublin pubs in busy Temple Bar are charging up to €10 (£8.60) for a pint of Guinness. Relative prosperity has a hollow ring. The main opposition party, Sinn Féin, smells blood. The son of a Mumbai-born GP and a nurse from County Waterford, Varadkar has been a taoiseach like no other. Predecessors such as Bertie Ahern and Enda Kenny loved to work a room, connecting. Varadkar is painfully shy, awkward in company and useless at the small talk that is the operating system of Irish politics. I interviewed him soon after he became taoiseach in 2017 – and in 37 years of dealing with politicians, I had never come across one like him. I concluded that Varadkar is wired differently. Bright and observant, he often says what he is thinking, but without a defensive filter. On many levels, he is an outsider. Personal popularity could not make up for wider disgruntlement. In the 2020 general election – Fine Gael’s only one under Varadkar’s leadership – the party lost 15 seats. But it remained in power by forming a coalition with Fianna Fáil, led by Micheál Martin, and the Green party. The Varadkar-Martin link-up has their parties sharing power for the first time since the foundation of the state, and marks the end of civil-war politics. Fianna Fáil calls itself “the Republican party”, but, compared with Martin, Varadkar is the more vocal supporter of a united Ireland – the most pro-unity leader in Fine Gael’s history. This nationalism is part of his complexity. Varadkar’s views may have been influenced by his family’s experience of British colonialism in India. Regardless, he has refused to cede the voice-of-nationalism space to Sinn Féin. He has been unequivocal in refusing ever to enter into coalition with them. On social issues, Varadkar is a liberal; but he promoted a conservative economic agenda, reflecting Fine Gael’s centre-right elements. When seeking the party’s leadership in 2017, Varadkar talked about leading a party for “people who get up early in the morning”. In a planned radio interview on his 36th birthday in 2015, when he was health minister, Varadkar came out as gay. Four months later, Ireland voted to legalise same-sex marriage and became the first country in the world to do so by popular vote. Varadkar’s leadership during the worst of the Covid pandemic may be remembered as his most impressive period in public life. His medical background as a qualified doctor helped. The system around him and key individuals within it responded well to the challenge. But Varadkar led with conviction. The way in which he navigated Brexit irked many of its supporters in Britain. In one Daily Mail column he was described as “the pipsqueak Irish prime minister, Lenny Verruca”. In 2019, Ireland’s ambassador to the UK, Adrian O’Neill, wrote to the editor of the Spectator, accusing the magazine of publishing “snide and hostile” articles about Ireland. The DUP, the only Northern Ireland party that campaigned for Brexit, had a strained relationship with Varadkar. But the Irish government’s determination to avoid the creation of a land border on the island of Ireland had almost universal support in its jurisdiction. Varadkar’s last formal engagement may be the north-south ministerial council, on 8 April, involving the restored power-sharing Stormont administration and the Irish government. It will be the first meeting since a video-conference event in July 2021. This week, as he attended his final summit of EU leaders in Brussels, Queen Camilla was in Northern Ireland at a poetry event in Hillsborough Castle, in the company of Sinn Féin’s Michelle O’Neill and the DUP’s Emma Little-Pengelly, the leaders of the devolved government. Across the porous border, in Dublin, Simon Harris was emerging as Varadkar’s likely successor. If elected, Harris will at 37, become Ireland’s youngest taoiseach. The leader-elect has already ruled out sharing power with Sinn Féin after the next election. The makeup of the next government is the conundrum that preoccupies and haunts Irish politics. Sinn Féin will be the largest party, but neither Fine Gael nor Fianna Fáil want to form a government with them. It’s an equation that troubled Varadkar. But it is no longer his problem. Tommie Gorman is a former Northern editor and former Europe editor of RTÉ, Ireland’s public broadcasting service