REX MURPHY: Oprah Winfrey, the Obama supporter fame left behind.

Oprah was the queen of all that she surveyed. She was regularly highlighted as one of the most, if not the most, influential persons in the United States. If she touted a book, it went to the top of the best seller lists. She waved a wand and the already famous were made more famous. And she was ardently “non-political.”

But four years ago, the House of Oprah made an epic decision: It chose to endorse Barack Obama. Oprah featured Obama on her show, with Michelle, and put the celebrated Oprah muscle to task for his campaign. It was a truly momentous event — the most powerful woman in entertainment endorsing a presidential candidate.

The move was timely. Obama had not yet crested to the great heights of adulation that marked the later stages of his campaign. Oprah endorsed him when it counted, then — having made her point — withdrew from the stage. I can’t think of a more significant moment in the modern intersection of the worlds of Hollywood and Washington, celebrity and power.

Was Oprah’s benediction a “tipping point”? Was it the moment when Obama jumped from being just another candidate to being a star in a class of his own?

Perhaps, but that was then. What of now? Well, something strange has happened. Oprah has lost her chi. She ended her long-time relationship with mainstream television and decided that she should have her own network. It is one of the very few examples of a person ordering her own self-exile. And the result is that she has simply ceased — in television terms — to be. I cannot recall a more precipitous drop in status, and in the influence status bestows, than Oprah’s almost complete fall from entertainment eminence.

Who speaks of Oprah now, save in valediction? Is she endorsing Obama this time? Who cares?

Everything Obama touches . . . .