Donald Trump is making good on his promise to “build a wall,” but I don’t think he even knows what that entails. In a move that should shock no one, Mexican President Pena Nieto canceled his trip to the United States and reiterated that Mexico would not, in fact, pay for the wall.

So, the United States is going to have a 20 percent import tax on all products brought in from Mexico. Let’s see how fast all the cheap business we do with the help of maquiladoras crashes and burns. For all the people that voted for Trump waiting for him to “revamp our failing economy,” let’s see how this goes for you.

Besides Trump’s misunderstanding of basic economics, he (and his constituency) fundamentally doesn’t understand how undocumented immigration is actually represented in this country. Besides his full-out denial of immigrants paying taxes and contributing to American society in every way, the majority of immigrants are not skipping across a line drawn in the sand; they come in cars, in planes, crossing the desert to make a better life for their families.

Building a wall across the entire border is not only impossible; its $15 billion dollar bill could instead go back into communities to make them safer. The border is already mostly monitored and fenced to begin with; besides that, there are running rivers, native lands, and businesses across the two countries. Moreover, undocumented immigration is not America’s problem, as sanctuary cities like Miami, Los Angeles and New York have shown. Immigrants – like my mom – are what makes this country great.

They don’t need to be kept out of this country, Donald Trump, you do.