Five years ago, I warned about the risk of a Donald J. Trump presidency. Most people laughed. They thought it inconceivable.
I was not particularly prescient; I come from Italy, and I had already seen this movie, starring Silvio Berlusconi, who led the Italian government as prime minister for a total of nine years between 1994 and 2011. I knew how it could unfold.
Now that Mr. Trump has been elected president, the Berlusconi parallel could offer an important lesson in how to avoid transforming a razor-thin victory into a two-decade affair. If you think presidential term limits and Mr. Trump’s age could save the country from that fate, think again. His tenure could easily turn into a Trump dynasty.
Mr. Berlusconi was able to govern Italy for as long as he did mostly thanks to the incompetence of his opposition. It was so rabidly obsessed with his personality that any substantive political debate disappeared….