A conservative challenged liberal Facebook friends to “make a case, not based on emotion” against Trump’s wall. Conservative buddies flooded his post with snide remarks about how this would be impossible for “deluded libs.”

“Okay, I’ll play,” I responded. To avoid being accused of bias, I explained that I would use only conservative sources to make my point. My primary source was a policy paper by the Cato Institute—a conservative, libertarian think tank—along with other conservative voices (listed below).

Here’s why I’m against the wall, I wrote:

1. Walls don’t work. Illegal immigrants have tunneled underneath and/or erected ramps up and down walls and simply driven over them. People find a way. When East Germany erected its wall, it created a military zone, staffed by booted, machine-gun carrying guards ready to shoot to kill. Yet thousands managed to make it to West Germany anyway. More to the point, do we really want to model ourselves after communist East Germany?

2. Most illegal immigrants are “overstayers.” They come to the U.S. legally—for vacations, jobs, schools, etc.—and then stay long past their visas. By 2012, overstayers accounted for 58 percent (the majority) of all unauthorized immigrants. A wall is meaningless here.

3. Walls have little impact on drugs being brought in to the U.S. According to the DEA, almost all drugs come in through legal points of entry, hidden in secret containers and/or among legit goods in tractor-trailers. A wall will have little to no impact on the influx of drugs into our country.

4. It’s environmentally impractical. Walls have a hard time making it through extreme weather. For example, in 2011, a flood in Arizona washed away 40 feet of steel fencing. Torrential rains and raging waters do serious damage. Also, conservative sources generally do not address the environmental harm that walls create, but there is plenty of documentation showing the potential for irreparable damage to both plant and animal life.

5. A wall would force the U.S. government to take land from private citizens in eminent domain battles. Private citizens own much of the land slated for the wall. The costs of the government snatching private land—and the legal battles that would ensue—are incalculable.

6. Border patrol agents don’t like concrete or steel walls because they block surveillance capabilities. In other words, they can’t mobilize correctly to meet challenges. So, in many ways, a wall makes their job more difficult.

7. Border patrol agents say walls are “meaningless” without agents and technology to support them. Are we prepared to pour countless billions annually—well after the wall is built—to create a nearly 2,000-mile militarized, 24-hour-surveillance border operation? Because according to patrol agents, that’s the only way a wall would work. Again, are we really going to use East Germany, a brutal communist state, as our model here?

Are we seriously going to model ourselves on East Germany and their wall? Photo: Keystone-France/Gamma-Keystone via Getty Images

8. Where barriers were built, there was little impact on the number of border crossers. According to the Congressional Research Center cited in the Cato report, after San Diego rebuilt a fence making it more wall-like—taller and more opaque—the structure “did not have a discernible impact on the influx of unauthorized aliens coming across the border” in the area. They simply came in elsewhere, primarily where natural barriers such as water or mountainous regions preclude a wall.

9. A wall has unintended consequences on other industries: For example, it blocks farmworkers from exiting when their invaluable seasonal work is done. Farmers are against the wall because it makes getting cheap seasonal labor almost impossible, as few American citizens want those jobs. And if seasonal workers do get in, a wall makes it harder for them to leave. It traps migrant farm laborers in our country.

10. Trump’s $5 billion is a laughable drop in the bucket for what would actually be needed. For example, according to the Cato Institute: An estimate for a border wall area that only covered 700 miles was originally $1.2 billion. How much did it cost in reality? $7 billion. And that’s only for 700 miles. Whatever we think it’s going to cost, experience shows us we must multiply it by more than 500 percent.

11. According to MIT engineers, the wall would cost $31.2 billion. Homeland Security estimates it at $22 billion. Given the pattern of spending mentioned in number 10 (plus Murphy’s Law), we’re talking about pouring endless billions into something that doesn’t even work. Of course, we taxpayers will be footing the bill, not Mexico. Given all the drawbacks, is this really the best use of our taxes?

As the conservatives of the Cato Institute put it, “President Trump’s wall would be a mammoth expenditure that would have little impact on illegal immigration.” It would also create many “direct harms,” including “the spending, the taxes, the eminent domain abuse, and the decrease in immigrant’s freedoms of movement.”

We must add, because conservative sources do not, that the environmental harms are likely to be severe.

In other words, the facts show that walls don’t work. Instead, they create even bigger, more expensive problems.