Walls don't work. Just ask the champions of open borders who have never tried them.
German Chancellor Angela Merkel said on Saturday that putting up walls will not solve problems caused by immigration, challenging one of U.S. President Donald Trump's core principles, during her visit to Mexico.
"Obviously the main reason for people leaving must be addressed on site first, which means putting up walls and cutting oneself off will not solve the problem," said Merkel, who has come under political pressure at home for opening German borders to more than one million refugees since 2015.
"It's an issue you can study well in the history of China with the (Great) Wall of China, you can study it in the history of the Roman Empire. Essentially, only when great empires have managed to forge sensible relationships with their neighbours and to manage migration has it been a success," she added.
"I don't think that by simply improving the border facilities you can solve the problem," she told a panel discussion alongside Mexican President Enrique Pena Nieto.
It can solve the problem quite well. If you actually do it.
But it's all in how you define the problem. If you define the problem as migration, walls work. If you define the problem as intolerance toward diversity, then of course they don't. But no doubt the Great Wall was a mistake and China should have allowed itself to be overrun by rampaging barbarians. It's worked out so well for Merkel's Germany.