When the politics of certain nations shift, it can have a ripple effect that extends through the surrounding region and sometimes even affects the world at large.
This is especially true when a sudden crisis looms and people find themselves having to flee their homelands to protect their families. When enough people are in this situation, it becomes harder for neighboring countries to keep tabs on who seeks to enter their borders and why.
And as these problems become more extreme, so too do their proposed solutions. There's also not only the question of how well responses to border crises can work, but what the intentions behind those responses are.
While diligence in working out the answers to these questions is needed, it's also true that the longer this takes, the easier it is for situations like the one unfolding at one Texas checkpoint to worsen.