sentences:  At the federal level the NDP has held strong influence over various minority governments, in particular a Liberal minority led by Pierre Trudeau from 1972-1974 during the 29th Canadian Parliament.During this period the NDP was successful in forcing the government to create a state-owned oil company, called Petro Canada.The NDP has also held influence over other Liberal-led minority governments during the Lester B. Pearson government (1963-1968) and the Paul Martin government (2004-2006).