Answer
Simon Coveney, the Minister for Housing, Planning and Local Government, was Varadkar's main opponent in the 2017 Fine Gael leadership election. The election was triggered by the resignation of Enda Kenny, who had served as Taoiseach (Prime Minister) since 2011. Varadkar, who was the Minister for Social Protection at the time, won the election by a narrow margin, securing 60% of the vote in the final round.