Giuliani left open the prospect of another White House run.

(CNN) — Rudy Giuliani told CNN Sunday the failure of his presidential bid this year didn’t mark the end of his political career — and that his future could include another White House run.

The former New York City mayor said that the economic environment this year may have presented too big an obstacle for any Republican presidential hopeful to overcome.

"If you had told me a year ago we would have a major economic crisis, I would've told you it would be very hard for any Republican," he said.

He wouldn’t rule out another run for the top spot. "No one knows whether you'll do something again until you come to the point of: 'Is it possible to do it again? Would you have a chance of winning?’ I mean, those are just things you can't evaluate right now," Giuliani said during a question-and-answer session with CNN International’s Hala Gourani.

Giuliani also wouldn’t rule out the the idea of serving in an Obama administration, though he said it was “unlikely” to happen.

"You never answer questions like that hypothetically," he said. “Very few people ever turn the president down, but that's an unrealistic situation."

Giuliani also left open the prospect of a run for New York governor against Democrat David Paterson. "I don't know if I'd be interested in it,” he said, when asked about the possibility of a gubernatorial bid. “But I'll think about it when the right time comes along."

Paterson, who took over as governor after Eliot Spitzer’s resignation, is planning a run in his own right in two years.