It was showtime at the Republican presidential debate on Tuesday, and the big surprise was the man in the spotlight - Ron Paul, the longest of longshots.

Paul, a nine-term congressman from Texas and the Libertarian Party candidate for the White House in 1988, stood out in a field of 10 Republican presidential candidates by standing up to front-runner Rudolph Giuliani in a spat over the September 11 attacks.

Paul initiated the exchange with Giuliani, the mayor of New York on September 11, by implying U.S. policies in the Middle East had contributed to the attacks in New York and Washington.

"Have you ever read about the reasons they attacked us? They attack us because we've been over there. We've been bombing Iraq for 10 years," he said.