Here’s a letter to Sen. Marco Rubio (R-FL):
You tweeted  the following, the illogic of which is breathtaking:
[email protected] frustration with #Mexico is understandable.
For years the U.S. has tried everything to get #Mexico to stop allowing their national territory from being used by 3rd country migrants as an open bridge to illegally transit to & cross our southern border
You here imply that the Mexican government could stop immigrants from crossing northward into Mexico on their way to the U.S. simply by being more willing to do so. If this implication is correct, then surely the U.S. government can similarly stop immigrants from crossing northward into the U.S. simply by being more willing to do so. Yet if the U.S. government has this power, then the U.S. government alone – and not the Mexican government – is responsible for allowing immigrants to continue to cross northward into the United States.
But if instead (and more realistically) the U.S. government cannot stop immigrants from crossing northward into the U.S. simply by being more willing to do so, then your accusation against the Mexican government is unwarranted. And by issuing it, you unjustly vilify the Mexican government for being unable to do what the U.S. government itself is unable to do.
Donald J. Boudreaux
Professor of Economics
Martha and Nelson Getchell Chair for the Study of Free Market Capitalism at the Mercatus Center
George Mason University
Fairfax, VA 22030
Other problems – some even deeper – infect Rubio’s tweet. Above I lazily point out only the most obvious problem.