CNN’s Republican debate was probably the hottest item on TV last night. But what about what the candidates actually said? Let’s look at 4 things the Republicans candidates got wrong (or not quite right) about immigration in the latest debate.

1. Birthright Citizenship Is a Crazy Idea, Unique to the United States

During the debate, Donald Trump states that “almost every other country” in the world, including Mexico, does not have birthright citizenship—laws allowing people to automatically gain citizenship in a country where they were born, regardless of the citizenship of their parents. This is not quite right. While it may be true that the majority of countries do not allow for birthright citizenship, at least 30 countries do, including Canada and, contrary to Trump’s statement, Mexico.

2. Illegal Immigrants Cost the U.S. Government Over $200 Billion Per Year

Donald Trump also said that illegal immigration costs the U.S. $200 billion per year. In a 2013 report, the Federation for American Immigration Reform estimated that the annual costs of illegal immigration at the federal, state and local level to be about $113 billion. Not only did Trump overshoot his figures, he also fails to take into account that economic benefits that illegal immigrants have on the American economy.

Illegal immigrants contribute approximately $7 billion per year into Social Security and about $1.5 billion in Medicare taxes. Additionally, they positively support the U.S. economy by spending millions of dollars per year, which helps to create much needed new jobs.

3. More ICE Agents Patrolling the Border will Help Reduce Illegal Immigration

Sounds like a good idea, right? Sure, except that Former president, George W. Bush, already tried this—and it didn’t work.

The U.S.-Mexico border is 1,951 miles long and touches four states. The U.S. Border Patrol, already with over 21,000 agents, is one of the largest law enforcement agencies in the United States.

During his tenure, Bush signed The Intelligence Reform and Terrorism Prevention Act of 2004 which allowed the hiring of an additional 10,000 agents. By doing so, he authorized the increase of border agents from 11,000 to 20,000, almost doubling the manpower. However, instead of improving, the number of illegals caught dropped from 1.2 million in 2005 to 541,000 in 2009 and has been on a downward trend ever since.

Now you could argue that the drop in numbers is because of the tougher enforcement, but that leads me to ask: if what we have is working, do we really need a wall?

4. A Border Fence Is Good for Americans

In the United States we have a doctrine called eminent domain. This allows the government to take over an individual’s private land for public use. If the border patrol fence is erected as per Donald Trump’s plan, landowners on the border will be forced to sell their land to the U.S. government, sometimes at a lower price than they would have received for selling the land in the open market.

Additionally, the U.S.-Mexico border crosses areas environmentally protected for several endangered species. The destruction and disruption of the land where these already endangered species reside threatens their chance for continued survival and negatively affects the local ecosystem and our nation as a whole.

Taking both the economic and environmental impact into account, the idea of a border fence is not in many Americans’ best interest. Nor is it in Trump’s if his agenda is to reduce government expenditure and control.