Complex sentence: Samson's partner in establishing the new party was Pierre Sévigny, a federal cabinet minister in the Progressive Conservative government of John Diefenbaker who had resigned in disgrace because of his relationship with Gerda Munsinger, who was later revealed to be a spy for East Germany.
Split into simpler sentences: Samson's partner in establishing the new party was Pierre Sévigny, a federal cabinet minister in the Progressive Conservative government of John Diefenbaker. Sévigny had resigned fromthe federal cabinet in disgrace because of his relationship with Gerda Munsinger, who was later revealed to be a spy for East Germany.