Barack Obama is failing as President and the US is in danger of sliding into a military dictatorship, says Gore Vidal, the American essayist and intellectual.

In an exclusive interview with The Times, Vidal, 83, reveals that he regrets switching his allegiance from Hillary Clinton to Mr Obama during last year’s campaign to secure the Democratic presidential nomination.

“I was hopeful,” he said of Mr Obama. “He was the most intelligent person we’ve had in that position for a long time. But he’s inexperienced. He has a total inability to understand military matters. He’s acting as if Afghanistan is the magic talisman: solve that and you solve terrorism.”