Elected to parliament in a volatile political period, Mahathir, as a government backbencher, launched himself into the main conflict of the day: Singapore's future, with its large and economically powerful ethnic Chinese population, as a state of Malaysia. He vociferously attacked Singapore's dominant People's Action Party for being "pro-Chinese" and "anti-Malay" and called its leader, Lee Kuan Yew, "arrogant". Singapore was expelled from Malaysia in Mahathir's first full year in parliament. However, despite Mahathir's prominence as a backbencher, he lost his seat in the 1969 election, defeated by Yusof Rawa of the Pan-Malaysian Islamic Party (PAS). Mahathir attributed the loss of his seat to ethnic Chinese voters switching support from UMNO to PAS (being a Malay-dominated seat, only the two major Malay parties fielded candidates, leaving Chinese voters to choose between the Malay-centric UMNO and the Islamist PAS).