Frontrunner Mitt Romney and rivals for the Republican presidential nomination will face off in a high-stakes debate ahead of New Hampshire’s primary.

Michele Bachmann has ended her bid to become the Republican presidential nominee and called on supporters to rally behind the party’s eventual choice.

Republican presidential hopeful Michele Bachmann’s campaign manager, Ed Rollins, and his deputy are leaving their roles.

Michele Bachmann won the Iowa straw poll on Saturday in the first big test of the 2012 Republican presidential campaign.

Six Republican presidential hopefuls will compete in the Iowa straw poll — an unofficial test of campaign strength.

Tom Petty has told US presidential candidate Michele Bachmann to stop using one of his songs as part of her campaign.

Michele Bachmann, a favourite of Christian conservatives and anti-tax Tea Party activists, kicks off her presidential campaign in Iowa on Monday.

US president Barack Obama announced his 2012 re-election bid on Monday, promising to "fight to protect the progress" the country had made.