New Delhi

A WELL-KNOWN Indian fashion designer, who had recently flown home from New York, said to me at a dinner in Delhi: “For the first time in a long time, I didn’t feel like coming back. I felt like it used to be in the old days, when we would go abroad and didn’t want to come back.”

The designer was referring to the malaise that has settled over this once hopeful country. People in India will give you many reasons for it. They will cite the growth rate — once nearing 10 percent, now barely 5 — they will talk of the corruption, in every sector from telecom to land to coal, that has totally discredited Prime Minister Manmohan Singh’s government; they will mention the reforms that never happened. And they are not wrong to talk of these things. But these are only symptoms. Not the cause of the gloom, but emanations from it.

What really ails the world’s largest democracy, and what has caused it to lose its footing at this crucial moment in its development, is that its oldest party, its ruling party, the party that invented dynastic democracy, the Congress Party, has found, in the person of Rahul Gandhi, an abysmal mediocrity for an heir. It makes for such sad reading, this tale of the failed crown prince, that it hardly bears telling, were it not for the fact that it has derailed the aspirations of a billion people.

The story began in 2009, when the Congress Party was re-elected at the head of an alliance of parties. At that point, Mr. Singh, the distinguished architect of India’s economic reforms, had been prime minister for five years. Although there are no term limits on the post, he was already in his late 70s. And his party, which had for so long sought legitimacy in the cult of the Gandhi family, felt it was time to put in place a succession plan: a restoration, after a gap of some two decades, of a Gandhi to the office of prime minister. Mr. Singh was set up as the able regent, Rahul Gandhi — grandson of Indira Gandhi — as the 42-year-old prince in waiting.