Any Conservative leader in this era has an extra millstone around his neck. The swing voters won't have any doubt in their minds in 2019 if Scheer or the party appear too friendly to Trump. The socially liberal/fiscally conservative or moderate voter may have doubts about Trudeau but any hint of evangelical or conservative Catholic activists being policy insiders will keep them home or hold their nose slightly to vote for the Liberals. Trump supporters here would vote Tory no matter what but they are too few to matter.