 Diefenbaker sought a pretext for a new election.Such an excuse presented itself when former Secretary of State for External Affairs Lester Pearson attended his first parliamentary session as Leader of the Opposition on January 20, 1958, four days after becoming the Liberal leader.In his first speech as leader, Pearson (recently returned from Oslo where he had been awarded the Nobel Peace Prize), moved an amendment to supply, and called, not for an election, but for the Progressive Conservatives to resign, allowing the Liberals to form a government.