Senator Kerry emerges as defence frontrunner

In 2004, the then Democratic presidential nominee, John Kerry, in handing the keynote slot at the party convention to a little-known Senate candidate from Illinois, gave Barack Obama the launchpad for a national career that would lead to the White House.

Now Mr Obama is reported to be considering the senior Senator from Massachusetts for the post of the country's next Defence Secretary. As the Obama administration enters its second term, the incumbent, Leon Panetta, is expected to step down within months and spend more time with his family in California. His replacement will face pressing strategic challenges, chief among them the orderly withdrawal of US troops from Afghanistan and the wrangle over cuts to the defence budget.

But more immediately, he or she will have to deal with controversy over the link between General John Allen, the top US commander in the war-torn country, and the extra-marital affair scandal that last week led to General David Petraeus's resignation as CIA director. General Allen has since become the subject of a probe into his correspondence with a Florida woman who approached the FBI after being harassed through emails from General Petraeus's lover.

For many, Mr Kerry was until now viewed as the natural successor to Hillary Clinton, who is expected to step down from her post at the head of the State Department.

A committed internationalist and chairman of the Senate Foreign Relations Committee, he is well known in capitals around the world.

But the White House is said to be keen on Susan Rice, the current US ambassador to the UN, for the role of the county's top diplomat. Instead, the Senator's CV – he is also a Vietnam War veteran – is being viewed by White House advisers as the right fit for the Pentagon job, which increasingly combines aspects of diplomacy, both domestically with US law makers and internationally with governments in countries where the US is militarily engaged, and strategic planning.

According to The Washington Post, this has landed him a spot on the shortlist. Other jobs said to be up for a refresh include the key posting at the Treasury department, with Tim Geithner also expected to depart at the start of the second term.

It remains unclear when exactly Mr Panetta will leave. Earlier this week, when quizzed on whether he would stay or go, he said: "Who the hell knows? My experience in Washington is you better do this day to day."