'You are giving me the highest honour I could ever receive,' he said at his Dallas headquarters, after being apparently urged formally to put himself forward by volunteer supporters in all 50 states.
While the Democrat candidate, Bill Clinton, expressed concern yesterday that Mr Perot's re-entry could split the anti-Bush vote on 3 November and hand the White House back to President George Bush, several polls suggest that the Perot candidacy may alter the final result only slightly .
A CNN poll released immediately after the announcement actually showed Mr Clinton expanding his lead to 17 points over Mr Bush even in a three-way contest. The poll gave Mr Clinton 52 per cent over 35 per cent for the President and 7 per cent for Mr Perot.
Mr Perot returned to the themes practised during his short-lived spring campaign, pledging to rid the US of its dollars 330bn ( pounds 190bn) budget deficit and break the 'political deadlock' of Washington.
His July decision not to run had been a mistake, he said, based partly on the belief that the main parties would start taking the deficit issue seriously.
'We gave them the chance, but they didn't do it,' he said.
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