Peterson was first elected as the Liberal Member of Provincial Parliament for London Centre in the 1975 provincial election. Less than one year later, he campaigned for the leadership of the party following Robert Nixon's resignation. Considered by some to be inexperienced, Peterson nevertheless came within 45 votes of defeating Stuart Smith on the third and final ballot of a delegated convention held on January 25, 1976. Smith represented the left-wing of the party, while Peterson was seen as representing its right-wing. Some blamed Peterson's loss on the banal delivery of his convention speech.

Peterson was re-elected in the provincial elections of 1977 and 1981, and ran for the Liberal leadership a second time after Smith's resignation in 1982. Again considered to be on the right of the party, he defeated the more left-leaning Sheila Copps on the second ballot of a convention vote, held on February 21, 1982. One of his most prominent supporters in this period was Keith Davey.

In government

The Liberals and NDP defeated Miller's government on June 18, 1985 on a motion of no confidence, and Peterson was sworn in as Premier of Ontario eight days later. After the expiration of the Liberal-NDP Accord in 1987, the Liberals called another provincial election, and were returned with a landslide majority, taking 95 seats out of 130--the most seats in the history of the Ontario Liberal Party.

Peterson's government introduced several pieces of progressive legislation. It eliminated "extra billing" by doctors, brought in pay equity provisions, and reformed the province's rent review and labour negotiation laws. His government also brought in pension reform, expanded housing construction, and resolved a long-standing provincial controversy by extended full funding to Catholic secondary schools. Peterson was also a vocal opponent of free trade with the United States in 1988. His administration was less activist in its later years, though it still introduced progressive measures on environmental protection, eliminated health insurance premiums, and brought in no-fault automobile insurance for the province.

The Peterson administration also developed a reputation for fiscal prudence, under the management of Treasurer Robert Nixon. The Liberal government was able to introduce a balanced budget for 1989-90 following several years of deficit spending in Ontario, at a time when deficit spending was commonplace in most of North America.

Peterson remained personally popular during his time in power, and some spoke of him as a future Prime Minister of Canada. Peterson improved his public speaking abilities in the early 1980s, and projected the image of an active, charismatic figure when in office. Some believed his image was perfectly suited to the young, urban professional demographic of the 1980s.

Warning signs

Both Peterson and his government were still popular at the beginning of 1990. The end of his career in politics came suddenly, and was the result of several factors.

The first was Peterson's prominent role in creating and promoting the "Meech Lake" constitutional accord. While initially popular, this attempt at revising Canada's constitution proved extremely divisive in most of English-speaking Canada. Many believed that it gave too many concessions to Quebec, while others believed that it weakened the federal government's authority in relation to the provinces. Peterson's continued support for the accord, in the face of increased opposition, damaged his personal popularity in Ontario. The accord was not endorsed by Manitoba and Newfoundland, and did not pass.

The second reason for Peterson's downfall was the controversy resulting from the Patti Starr scandal. Starr, a prominent Liberal fundraiser, was found to have improperly diverted money from land-development and charitable organizations to the provincial Liberal Party. She was eventually sentenced to six months jail time. Although no-one in Peterson's administration was accused of criminal activity, the scandal eroded public confidence in the integrity of the ministry.

The third reason was the weakening North American economy. Productivity levels were falling throughout the United States and Canada during this period, and were likely worsened in Ontario and other jurisdictions by the recent passage of a Free Trade Accord involving the two countries. While there was little that Peterson, or any other Ontario Premier, could have done to prevent this downturn, it weakened his government's reputation for fiscal competence. (Indeed, the government's projected surplus budget for 1990-91 ultimately yielded a deficit of at least three billion dollars.)

Legacy

Peterson's 1985 election victory was part of a trend in the improvement of Liberal fortunes in Canada. Prior to that Ontario election, the future of the Liberal Party looked bleak. They governed in no province, and, federally, were down to 40 seats. In some provinces, the Liberals had been completely wiped from both federal and provincial representation in the legislatures. Slowly, beginning in Ontario with Peterson's surprise government, electoral prospects were improving for both federal and provincial members. By October, 2003, the Liberals were in power federally, and in each of the three largest provinces in the country, as well as in Newfoundland. In four provinces, they formed the opposition.

After politics

David Peterson was the founding chairman of the Toronto Raptors of the National Basketball Association, and was a member of Toronto's Olympics Bid Committee. Since leaving politics, he has been a professor at York University in Toronto, a senior partner and chairman of the Toronto law firm Cassels, Brock & Blackwell, and has been director or member of several charitable, cultural, and environmental organizations. He is or has been a member on several corporate boards, being particularly associated with the Rogers family of businesses. In his legal practice he provides international advice to a wide range of clients about public policy issues and government affairs in Canada.

In 1999, Peterson found himself at the center of controversy due to his membership on the board of YBM Magnex, a firm which was discovered to have links to the Russian mafia. Peterson maintained that he was unaware of illegal activities at the company, and referred to the accusations against him as "guilt by association". A subsequent investigation by the Ontario Securities Commission found that Peterson's actions met "the legal test of due diligence", but expressed disappointment that he had not shown more leadership on the board. A 2004 report from the Globe and Mail newspaper notes that Peterson was chastened by this experience, and has become "a cautious and more conscientious director" since this time.

Since 2003, Peterson has been contracted by the federal government to be its Chief Negotiator, in talks with the government of the Northwest Territories and Aboriginal leaders, to transfer federal powers over lands and resources to the territory. Mr. Peterson has been quoted as noting this as an opportunity to try again and play a part in nation-building.

Peterson has continued over the years as a powerful organizer and fundraiser for the federal and Ontario provincial Liberals. In May 2005, he played the central role in helping Belinda Stronach, a federal Conservative MP, to cross the floor to the ruling Liberal Party, days before a crucial confidence motion on the federal budget of Paul Martin's Liberal minority government. The defection proved critical to the survival of Martin's government, with the final outcome of the budget vote 153-152 in favour of the government.

Peterson became chancellor at the University of Toronto effective July 1, 2006.   (Source - Wikipedia)