In 1999, President Bill Clinton stood across the street from New York’s Pennsylvania Station with the state’s governor and its senior senator to announce plans for transforming the area into a modern gateway for the nation’s biggest city. Presidents do not often appear at news conferences about train stations. But Penn Station, in Midtown Manhattan, was the busiest transportation hub in North America, and Mr. Clinton had made public transit a priority. He and Gov. George E. Pataki posed beside a miniature model of a grand new train hall, while Senator Daniel P. Moynihan extolled its future grandeur. “Penn Station is the start,” Mr. Moynihan said, “and we will find — when we complete this project — that suddenly all will seem possible.” More than 25 years, five presidencies and four governors later, the plan to rebuild Penn Station is nowhere near completion. For the 600,000 people who pass through every day, Penn Station is indispensable. It remains the busiest transit hub in the United States, with nearly double the number of daily passengers as the busiest airport, Hartsfield-Jackson Atlanta International. Much of the Eastern Seaboard might grind to a halt without it. It is also widely abhorred. Passengers descend into a gloomy, dimly lit warren of overcrowded concourses, much of it layered in grime and corroded by decay, sitting above an array of subterranean tracks whose age creates regular snarls and delays that cost New York millions of dollars in lost productivity each day. More broadly, it is a stagnant symbol of something deeper in America, a condition that afflicts so many attempts to get big things done: inertia. Again and again, when America undertakes big projects, politics and government get in the way. The owners of Madison Square Garden, the arena that sits on top of Penn Station, have rejected proposals to move it. Countless ideas for making Penn Station grander and more commuter-friendly have been floated and shelved over the decades.