Success breeds failure. That’s one of the melancholy lessons you learn in life. The success of policymakers in stamping out inflation in the 1980s and minimizing recessions for two decades also produced policies that produced the bust in housing prices and financial collapse of 2007-08.

It’s the same in politics. Strategies and tactics that seem certain to produce victory can eventually produce defeat. Prognostications that one party or platform will prevail far into the future usually turn out to have a surprisingly early sell-by date.