President Trump says the Mexico border wall is coming

CAMPO, CA - OCTOBER 08: A U.S. flag put up by activists who oppose illegal immigration flies near the US-Mexico border fence in an area where they search for border crossers October 8, 2006 near Campo, California. The activists want the fence expanded into a fully-lit double-fenced barrier between the US (R) and Mexico. US Fish and Wildlife Service wardens and environmentalists warn that a proposed plan by US lawmakers to construct 700 miles of double fencing along the 2,000-mile US-Mexico border, in an attempt to wall-out illegal immigrants, would also harm rare wildlife. Wildlife experts say cactus-pollinating insects would fly around fence lights, birds that migrate by starlight in the desert wilderness would be confused, and large mammals such as jaguars, Mexican wolves, Sonoran pronghorn antelope, and desert bighorn sheep would be blocked from migrating across the international border, from California to Texas. (Photo by David McNew/Getty Images)

The President has signed the order for construction on the Southern border wall with Mexico to begin. Trump says Mexico will pay for it, but there's reason to doubt that.

President Donald Trump made a number of announcements Wednesday, including the much discussed, "wall," between Mexico and the United States.

Trump says that construction of the border wall will begin in the coming months.

White House press secretary, Sean Spicer, insists that Mexico will pay for the wall, "one way or another," while the Mexican government insists that it will not.

Since the wall was first suggested, there have been lots of questions about making such a project a reality.

Melissa Del Bosque has been looking into these questions. She covers stories from the U.S.-Mexico border for the Texas Observer. She joined Take Two host A Martinez to talk about what's possible in terms of building a wall - and what's not.

On the substance of the executive order

"We're still waiting to see the substance. I know his press secretary is ... announcing signing the executive order for the wall, but I don't see any talk about how long it will be, how many miles other than president trump's renewed commitment saying that Mexico is definitely going to pay for the wall 100%."

How the President could get Mexico to pay and the likelihood of it happening

"What I suspect he's going to do in his threats over renegotiating NAFTA he's going to try and strong arm them through some kind of renegotiation and NAFTA making them pay for the wall as a concession to some sort of trade deal or something. That would be my guess. I know President Peña Nieto is scheduled to be meeting with [Trump] next week. I'm sure we're going to hear much more about it in the coming days.

"Already political leaders in Mexico are telling him not to even go to the United States because it's such an insult, this announcement from Trump. I'm sure there will be some sort of negotiation, some sort of talk, it's going to be a long and grinding process. "

On how expensive this would be

In Texas, they've talked about between $7 and $9 million a mile. We've already spent $2.4 billion on 650 miles of fence that we already have built. I've seen projections anywhere from $8 billion to $25 billion or more. This is the thing: All of this is done by private defense contractors and developers. This is a huge stimulus for them. So it all depends on the deal they negotiate with the government. It's a massive infrastructure deal.

To hear the full audio click the blue player above.