Pres. Putin, like Pres. Trump, is a very wealthy man. He is a pragmatist and wants to preserve his financial portfolio - he won't go to war over Syria.
Many places the border with Canada is marked by a single strand of barb wire fencing. Of course, the Mexican border needs a wall to keep the wtbacks out.
But how many Canadians want to come to the U.S. with the way the crime rates are here? ;)