This politician justified a turn to austerity by claiming that it would “open a parenthesis.” This politician gained leadership at the Épinay Congress after losing an election as the leader of the FGDS alliance. A rival party leader refused to use the Observatory Affair to discredit this politician, who lost his seat in 1958 when the SFIO did not remove its candidate. This politician named a doctrine against extraditing terrorists convicted over acts from the Years of Lead. Gaston (-5[1])Defferre (-5[1])was an important (10[1])ally of this president, whose Defense Minister Charles Hernu resigned after the sinking of the Greenpeace ship Rainbow Warrior. As president, this politician entered the first “cohabitation period” after appointing Jacques Chirac as his prime minister. For 10 points, name this first President of France from the Socialist Party. (10[1])■END■ (0[1])