U.S. border agents in Canada got new powers with Pre-clearance:Bill C-23.

Bill C-23, introduced by Public Safety Minister Ralph Goodale which likely to pass in the current sitting of Parliament will give U.S. border guards new powers to question, search and even detain Canadian citizens on Canadian soil .

The Bill C-23 could also erode the standing of Canadian permanent residents by threatening their automatic right to enter Canada, says Legal experts.