Confused about Donald Trump's border wall? Here are 7 essential reads

Primary purpose of building barrier is to reduce number of undocumented immigrants crossing border

On the campaign trail, Donald Trump promised Mexico would pay for a border war separating it from the U.S.

With that unlikely anytime soon, the president has been demanding Congress include funding for his proposed barrier in the budget lawmakers are hastily trying to finish by April 28. This has risked a government shutdown.

Now, however, Trump appears to be backing away from his ultimatum and may be willing to wait for the funds until later this year.

So why does Trump want to build a wall? What are the costs? And why should we care?

Our academic experts have weighed