How the economy — and Philadelphia — could determine the presidential election

The race for the presidency is in full swing, and the state of Pennsylvania — and more specifically Philadelphia — may well decide who wins.

This forecast is based on a model of presidential elections that my colleagues and I at Moody’s Analytics have been using to predict who will be the next president in elections going back to Bush vs. Gore in 2000. The model predicts whether the incumbent presidential candidate, Joe Biden in this election, will win the popular vote in each state and the District of Columbia,...