Responding to this challenge was, he felt, a "call of duty" that could not be ignored. As a result, despite holding the post of Canadian Ambassador to Yugoslavia and Bulgaria, he formally asked for "leave of absence" in 1979 from External Affairs in order to stand for Parliament and help with the 1980 Quebec Referendum. When this permission was refused, he resigned from External Affairs, thus effectively ending his career. He returned to his native Montreal to stand as Conservative Party candidate in the riding of Lasalle, a Liberal Party stronghold, and also to help to mobilise the Federalist "No" vote in Quebec.