U.S. President Barack Obama has extended his stay at the White House for another four years but his top diplomat, Secretary of State Hillary Clinton, has opted out for another tour in the Obama Cabinet come the fresh term that starts January 2013.

Citing the gruelling schedules of running the foreign affairs dealing of the world's most powerful nation, Ms Clinton has earlier declared that she would beg off from further fronting the United States.

Her stint, analysts said, can be characterised as beyond exemplary considering that she served the man who sidelined her ambition to follow the footsteps of her husband, former U.S. President Bill Clinton.

Mr Obama had frustrated Ms Clinton's bid of writing history, by becoming the first female American president, though the former will forever be regarded as the first black president elected in a nation that only decades ago grappled with civil rights and segregation issues.

Setting that aside, Ms Clinton appears bent on taking a break from punishing duties required of her by the State Department, though analysts noted that the demands were amply met by the jet-setting secretary, who U.S. media reports said clocked the most flying hours among the previous bosses that held the coveted cabinet portfolio.

Speculations also abound that Ms Clinton wishes to recharge and prepare for a second presidential run on 2016, aiming to extend the Democratic Party's dominance in Washington after Mr Obama's final term.

While nothing is definite yet, including the fact that Mr Obama could prevail upon on Ms Clinton to stay a little bit more, names started sprouting out as soon as the Democrats realised that the White House is theirs for four more years.

So to whom Australia would mostly deal with in the new Obama administration, in the event of a "graceful exit" for Ms Clinton?

The strongest contender, according to UK-based The Guardian, at the moment is Massachusetts Senator John Kerry, who worked closely with Mr Obama for his successful reelection bid.

On that note alone, Mr Kerry indeed can be considered a likely shoo-in for the top Obama cabinet apart of course from his sterling service record at the U.S. Senate, which was preceded by his stint in the Vietnam War.

He also ran but lost against former U.S. President George Bush but that episode of defeat should be eclipsed by his acumen in foreign relations, The Guardian said, which was further shaped by his being chair of the senate foreign affairs committee.

The only major factor going against Mr Kerry is the notion that his joining the cabinet could lead to the Democrat losing its grip in the U.S. Senate, a possibility that Mr Obama would definitely consider prior to opening up the State Department door for the senior senator.

Or the senator would likely have to make way for Susan Rice, currently serving as the U.S. ambassador to the United Nations, who The Guardian said was the name earlier floated in case her boss, Ms Clinton, prove true pronouncement of vacating her post.

But Ms Rice carries a heavy baggage at the moment, analysts said, stemming from the debacle in Libya in which the U.S. ambassador and three other embassy officials were killed in attacks on September this year that she initially labelled as isolated incident.

Ensuing intelligence reports, however, strongly suggested that the storming of the U.S. consulate office and safe house in Benghazi, Libya was planned and launched by terrorist-aligned groups.