NDP The riding was first created in 1966 with the Town of Whitby, the City of Oshawa, and part of Whitby Township, which were previously part of the riding of Ontario. In 1967, its name was changed to "Oshawa—Whitby." In the Ontario riding, the previous election was competitive, with the PCs, Liberals, and NDP all being within about 6500 votes (10%) away from each other. In 1968, the election was very close. There were over 45,000 votes cast and all 3 candidates were within 325 votes of each other. NDP candidate Ed Broadbent won, beating PC Michael Starr, who won the previous election in the riding of Ontario, by 15 votes. Broadbent and Starr would once again run against each other in the 1972 election. It was also a close race, with Broadbent beating Starr by 824 votes. In the 1974 election, Broadbent had increased his lead to 11,000 votes, and his vote count was almost as much as the Liberal and PC candidates combined. This had happened at the same time as prominent New Democrats such as David Lewis lost their seats. Shortly after the 1974 election, Broadbent was appointed Parliamentary leader of the NDP. In 1975, Broadbent was elected leader of the NDP. In 1976, the riding was modified to now only include the City of Oshawa and its name was changed back to "Oshawa." In 1979, a writer for Maclean's described Broadbent's re-election chances as "considerably better" than his chances in 1968. He ended up being re-elected by a similar margin, though this time it was over a PC instead of a Liberal. By this point, the riding was an NDP stronghold and they continued to win elections by large margins, increasing their margin of victory to 12,000 votes in 1980. Shortly afterward, Prime Minister Pierre Trudeau invited Broadbent to join his cabinet, but Broadbent ultimately rejected his offer. In 1984, Broadbent held on to the seat by a margin of 2000 votes despite the landslide that the PCs won nationally. In 1986, the riding was modified to exclude the area north of Rossland Road. In 1988, Broadbent would increase his margin of victory to about 4,400 votes over the PCs. In 1989, Broadbent resigned as NDP leader and he announced his retirement as MP later that year. He left parliament on December 31, 1989. By mid-1990, before the by-election happened, the government of Prime Minister Brian