From 1984–1988, Netanyahu was Permanent Representative of Israel to the United Nations. In 1993, he was elected as the Chairman of Likud, becoming Leader of the Opposition. He went on to defeat the incumbent Prime Minister Shimon Peres at the 1996 election, and was appointed as Israel's youngest-ever Prime Minister. After serving a single term, Netanyahu and Likud were heavily defeated in the 1999 election by Ehud Barak's One Israel party; Netanyahu chose to retire from politics entirely, and entered the private sector. However several years later, after his successor as Likud Chairman, Ariel Sharon, became Prime Minister, Netanyahu was convinced to return to politics, and served as Minister of Foreign Affairs and Minister of Finance. As Finance Minister, Netanyahu initiated major reforms of the Israeli economy that were credited by commentators as having significantly improved Israel's subsequent economic performance. Netanyahu later clashed with Sharon, eventually resigning over disagreements regarding the Gaza disengagement plan.