The examples of the 2006 Liberal and 2012 NDP leadership races suggest that no major candidate was able to give his party the sort of boost demonstrated by Justin Trudeau and the Liberals in a recent Nanos survey. In polls taken by the same firms before and after Brian Topp’s announcement in mid-September 2011 that he would run for the leadership of the NDP, the party actually suffered a drop of about three points. Thomas Mulcair’s announcement, made a month later, also had no positive effect on the national support of the New Democrats: it dropped by about 1.5 points. In 2006, announcements by Stéphane Dion and Michael Ignatieff at the beginning of April corresponded with an insignificant 0.5-point drop for the Liberals in polls conducted by the same firms before and after, while Bob Rae’s announcement at the end of April was greeted with another 0.5-point decrease. Read the full article.