Paying for 'Trump's wall'

Donald Trump has suggested we build a wall on our border with Mexico, primarily to control illegal immigration. Since Trump made his suggestion, there has been lots of political commentary and criticism of the idea, including the recent comments of Pope Francis, which were not supportive of the idea, to say the least.

One of the more practical questions was how the wall would be funded. The answer to this seems to be in the renegotiation of various trade relationships with Mexico, including taxing the importation of U.S. market products built and assembled in Mexico. This, of course, will prove to be a very controversial and complex process, as many different political and economic equities will be in play.