A country without a border is no country at all, I'm sure you have heard the same thing repeated over and over again, But it's true every major civilization on earth have had walls and borders. Even Moses in The Bible while leading the people out of Egypt asked to cross into a country and a King said no but God didn't punish the country that wouldn't allow them to enter! If he did I've never read it, in closing America should be protected with whatever it takes!
Without known exception, everyone has barriers to control entry to their property. In your home, you have walls with lockable doors to restrict access to various rooms of your house. You house also has walls around it with at least one lockable door to restrict access. Beyond that, many people have walls such as fences to prevent unwanted people on their property. Seeing that this country belongs to us and has had a history of being trespassed on, a fence is necessary to protect what is ours.
Some may feel that a fence eliminates cooperation between countries but this is far from the truth. It only helps eliminate unlawful entry. Seeing that we would still have access point along the fence means that any legal crossing can be done. If a person wants to cross for legal reasons they can, if a person wants to cross for illegal reasons, then obviously they should not be allowed access. If you knew that there was someone in your town that wanted to take things from your home, would it be moral for you to keep them out with walls and controlled entrance? Of course, to do otherwise would be foolish.
In poll after poll, and election after election Americans have overwhelmingly supported securing the border with Mexico and endorsed a border fence. It is therefore without question democratic to build the fence. Furthermore a border fence could help hinder or end the operations of the drug cartels and human smuggling, thus bringing great relief to people on both sides of the border. It is thus the moral thing to do as well.
Ignoring the cost and the manpower, a fence between the USA and Mexico would not be moral, because it would encourage racism and xenophobia in Americans. And also- while some people who cross illegally are drug traders or other criminals, most are perfectly good people who more than deserve a life in the "land of the free." Denying them this chance is not moral, no matter what Trump says or how big his "big beautiful door" is.
With increased travel and communication, the world is becoming smaller and people are often living and working in different regions throughout the course of their lives. With this kind of trend continuing to advance, building a 700 foot border fence between the US and Mexico, who should be cooperative neighbors, is an outdated idea that is a waste of resources and a step socially in the wrong direction. Instead we should strive to work together as a global, international, intercultural community for everyone's benefit and stop focusing on national and cultural differences.