[dropcap]I[/dropcap]f all politics is local, as Tip O’Neil famously said, then this year local politics is also national – or maybe international.

That was driven home again last week when President Trump announced he will pull the United States from the Paris climate accord, saying he was elected to represent Pittsburg, not Paris.

The local implications are profound in several ways. First, the chairman of the committee that oversees science, technology and climate legislation in the...