The issue

President Trump unveiled today an executive action to get to work on his wall on our border with Mexico.

The facts

Trump wants a 1,000 mile wall, constructed of concrete and steel, between 35-60 feet high. The other 1,000 miles of the border won't need a wall because of natural obstacles, including mountains and deserts. Trump says the wall will cost $8-12 billion, but the MIT Technology Review took a more critical look and predicts between $27-40 billion.

There's already about 650 miles of fencing on the border, courtesy of a 2006 law signed by George W. Bush. The effort focused on high traffic areas for border crossings of illegal immigrants and drugs, and cost a little less than $3 billion. Previous attempts to build a bigger wall or install more high fencing stalled in Congress.

What's next: Trump plans to have Congress pay for the first part of the wall using that 2006 law. He claims he'll get Mexico to pay us back using NAFTA re-negotiations and by potentially freezing remittances from Mexican nationals in the United States. Mexico says that won't happen.