On June 6, Prime Minister Boris Johnson survived a vote of no confidence from the Parliamentary Conservative Party. The vote was triggered by 15 percent of Tory Members of Parliament (MPs) writing to the chair of the 1922 Committee, which represents backbenchers. Thus far, six of the last nine leaders of the Tory Party have faced a leadership challenge of some sort while in office. Yet, while Johnson has joined the list of leaders who survived such a vote, the results of the ballot show that his leadership of the party in the long term remains precarious. How bad were the results? While the relatively low threshold for a vote means Johnson is far from the first leader to face …