If Canada seeks to retaliate over U.S. president-elect Donald Trump's tariff threat, the government should hit the U.S. where it hurt would both economically and politically, some trade experts suggest.

Canadian officials and experts believe that the jump in illegal crossings has been fueled primarily by immigrants arriving in Canada from India on tourism or other temporary visas.

While the announcement is almost certainly bluster to bring attention to illegal immigration and fentanyl smuggling, there are several reasons why it is so risky.