Though perhaps not in the way she intended.
For her edification, I offer her this link to a New Yorker article about the Berlin Wall, published in 1962.
If she reads it, she will learn:
Walls work to keep poorer people from richer people, cementing the disparity.
Walls work to turn borders into police states, ignoring the basic freedoms of citizens on both sides.
Walls work to separate families, friends and lovers.
Walls work to increase unemployment when the workers are on one side and the employers are on the other.
Walls work to embolden politicians as disparate as John Kennedy and Ronald Reagan to decry their existence.
Walls work to increase tension and distrust.
Walls work to become symbols of failed policies and misguided goals -- at least until the next ignoramus suggests that someone should build one.
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Monica, however, is wrong about one thing: Walls never work for long. Freedom always wins eventually.