Trump's Wall will make us less safe
It is:
An environmental hazard - As designed as it is it will critically disrupt life in the area with endangered species in the balance.
A legal hazard - There are many ways the construction of the wall can be used for money laundering and other forms of financial fraud.
A cognitive hazard - People are coming up from the southern border, in many cases because of US policy. If they are fleeing MS-13, let's not forget MS-13 is a byproduct of the brutal Salvadoran civil war. If they are fleeing brutal economic conditions in Central America, let's not forget that massive income inequality is a result of the "anti-communism" the US government promoted and engineered coups to produce. Building a wall so we don't have to see the human consequences of Operation Condor or PBSUCCESS is a dangerous mode of thinking. "Out of sight, out of mind" is not a healthy way to approach problems.
A democratic hazard - Walls work both ways, it can keep people out, but it can also keep people in. In the rise of authoritarianism, that should be concerning.