Mitt Romney and his Republican advisers claim momentum is on their side as the US presidential election enters the final stretch.

Grover Norquist is the President of Americans for Tax Reform which has persuaded many Republican politicians, including Mitt Romney, to sign a pledge opposing tax increases.

But just how credible is Governor Romney's plan of low taxes and spending cuts?

Grover Norquist talks to Stephen Sackur.

You can watch the full interview on BBC World News on Wednesday 31 October at 03:30, 08:30, 15:30 and 20:30 GMT and on the BBC News Channel at 0430 on Wednesday 31 October and at 0030 on Thursday 1 November.

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