..the Berlusconi parallel could offer an important lesson in how to avoid transforming a razor-thin victory into a two-decade affair. 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; it focused only on personal attacks, the effect of which was to increase Mr. Berlusconi’s popularity. His secret was an ability to set off a Pavlovian reaction among his leftist opponents, which engendered instantaneous sympathy in most moderate voters. Mr. Trump is no different.