WASHINGTON (AFP) - US President Barack Obama has one wish for the Republicans trying to succeed him: that the odds are ever in their favour.
On Thursday, Obama poked fun at the ever-increasing "interesting bunch" of politicians vying for the Republican presidential nomination in the 2016 race, which now stands at 15.
"We've got some healthy competition in the Democratic Party, but I've lost count on how many Republicans are running for this job," the US leader said in a speech to students in the Midwestern state of Wisconsin.
"They will have enough for an actual Hunger Games," he joked, referring to the best-selling young adult novels, later transformed into successful movie blockbusters, about a bloody reality TV contest among children and teens in a dystopian future.
Wisconsin Governor Scott Walker, who welcomed Obama to his state on Thursday as he descended from Air Force One, signalled that he was joining the presidential fray, making him the 15th major Republican in the White House hunt.
The race features six current or former governors, five current or former senators, a former high-powered business executive and a neurosurgeon.
Former secretary of state Hillary Clinton is the Democratic frontrunner by a wide margin.
Primary elections begin in January 2016, leading up to the presidential election in November that year.
Separately, US senator Jim Webb of Virginia, a Vietnam war veteran who served as secretary of the navy, announced on Thursday he will be challenging Democratic frontrunner Hillary Clinton for the Democratic nomination.
"After many months of thought, deliberation and discussion, I have decided to seek the office of the presidency of the United States," Webb said in a Facebook post.
Webb's campaign is a long shot by any measure, but he is counting on appealing to voters from both sides of the aisle, his opposition to the invasion of Iraq, and his experience as a decorated US Marine to distinguish himself in the 2016 race.
"I understand the odds, particularly in today's political climate where fair debate is so often drowned out by huge sums of money," Webb said, adding that "more than one candidate" for president intends to raise US$1 billion or more this election cycle.
"We need a president who understands leadership, who has a proven record of actual accomplishments, who can bring about bipartisan solutions, who can bring people from both sides to the table to get things done."
Webb, 69, is the fifth candidate seeking the Democratic nomination, after former secretary of state Clinton, Vermont's independent Senator Bernie Sanders, former Maryland governor Martin O'Malley, and former senator and governor Lincoln Chafee of Rhode Island.