Washington, September 1 (RHC)-- Republican presidential pre-candidate Scott Walker, a staunch advocate of securing the southern border of the U.S. with Mexico, says building a northern wall on the U.S. border with Canada is a “legitimate” idea. 

Walker, who is the governor of the U.S. state of Wisconsin, told reporters that the idea was brought up to him in a recent town hall meeting in New Hampshire. 

The notion of a wall on the northern border is a shift from the current rhetoric in the race which has focused on beefing up security on the border with Mexico, where millions of immigrants have illegally entered the United States. 

Republican frontrunner Donald Trump has consistently called for the construction of a towering wall along the border with Mexico.  The issue has become a hot topic for Republicans since the first GOP debate earlier this month. 

Walker surged into the top tier of the GOP race in winter but his candidacy has wilted in a campaign season dominated by Trump.