Fox News host Martha MacCallum suggested the construction of a border fence would be a cost-effective strategy for dealing with the influx of children fleeing Central America across the U.S.-Mexico border, but she underestimated the real cost of construction by billions of dollars. 

On July 8th, Politico reported that President Obama requested $3.73 billion in emergency funds from Congress “to address the influx of child migrants crossing the Southwest border and Rio Grande from Central America.” The funds would be used for border enforcement, humanitarian assistance for unaccompanied children, and immigration courts. 

During an interview with Rep. Ted Poe (R-TX) on the July 9 edition of America's Newsroom, MacCallum criticized the Obama administration for requesting $3.7 billion to address the humanitarian crisis which she claimed would only “plug the hole” when the “most recent estimate” for the cost to build border fence was only $6.5 billion:

MACCALLUM: 3.7, and we just listened to sort of a detail of where the money goes -- a lot of it is into facilities and for judges and that kind of thing as you say. It was interesting -- we looked back this morning at the latest estimate -- the most recent estimate we could find for what it would have cost to build the fence across the border and that's about six and a half billion dollars. So now you've got a 3.7 billion dollar request to basically -- you know -- plug the hole and take care of the people who came through it.

But MacCallum is wrong. According to the New York Times, the $6.5 billion figure MacCallum cited was merely an estimate of the cost to “deploy, operate and maintain” the existing border fence, which currently covers 650 miles, not the cost to extend the fence across new territory. In fact, the Times also reported that Customs and Border Protection projected the cost of finishing one fence across the southern border of the U.S. to be more than $22 billion, not including costs to acquire land and maintain the fence:

In 2009, the Congressional Search Service reported that the Department of Homeland Security had spent roughly up to $21 million per mile to build a primary fence near San Diego. The cost had ballooned as the fence extended into hills and gullies along the line.

The same year, Customs and Border Protection estimated costs of building an additional 3.5 miles of fence near San Diego at $16 million per mile. Even this lower figure would yield a rough projection of $22.4 billion for a single fence across the 1,400 miles remaining today.

These estimates do not include the costs of acquiring land, nor the expense of maintaining a fence that is exposed to constant efforts by illegal crossers to bore through it or under it or to bring it down. In March, Customs and Border Protection estimated it would cost $6.5 billion “to deploy, operate and maintain” the existing border fencing over an expected maximum lifetime of 20 years. The agency reported repairing 4,037 breaches in 2010 alone.

Fox continues to offer misinformation and advocate anti-immigration policies, recommending the federal government respond to the increasing numbers of of children fleeing gang violence in Central America by building multiple fences and militarizing the border.