He's best known for his hard line positions on immigration, and he's formed an exploratory committee for a presidential run in 2008.

NPR: Tancredo on the Presidency, and Immigration

At the end of December Mr McCain, now a third-term senator for Arizona (with a Vietnam record to match Mr Kerrey's), formed his exploratory committee and so became the first Republican to take a place on the official starting-line.

ECONOMIST: The hopefuls line up, hands held out