The sky was reliably clear over May Day parades in the Soviet Union, not because it never rains in Moscow but because the Kremlin would order the dispersal of any clouds. This was done with blasts of silver iodide, or dry ice, provoking precipitation in the morning so none fell on Red Square in the afternoon. That is what “making the weather” involves in authoritarian states. The supreme ruler dictates what will appear in the news bulletin and the subsequent meteorological forecast. Setting the agenda is trickier in democracies, where the market for public attention is competitive. It is harder for oppositions than governments. The hypothetical realm of what might happen under a different government is rarely more relevant to the distracted voter than whatever the actual prime minister is doing right now. Governments can make laws; oppositions can only make promises, which are a much-debased currency in British politics. On the metric that counts, Keir Starmer is succeeding in a field where most fail. He is preferred to Rishi Sunak as a possible prime …