WASHINGTON: As Hillary Clinton prepares to step down as America's top diplomat, no one quite believes she and husband Bill will disappear from the US political scene they have dominated for some two decades.

Despite questions over whether the secretary of state was to blame for security lapses before September's attack on the US consulate in Benghazi, Clinton remains the most popular figure in the administration.

The New York Times dubbed her the “rock star diplomat” and she has been met by cheering crowds in places as different as the Mongolian presidential palace and Georgetown University in Washington.

In her four years at the helm of US diplomacy, Clinton has criss-crossed the world, racking up more countries than any of her predecessors and tirelessly pushing democracy and what she calls “smart power”.

And, despite her repeated denials, many people remain convinced that she will once more try to run for presidential office. Amid the bitter political climate of a close election year her approval ratings still stand in the high 60s, and some analysts believe the Democratic Party nomination in 2016 could be hers for the asking.

She came close in 2008 only to see Barack Obama snatch the nomination from her, leaving her to claim the votes she won amounted to “18 million cracks” in the glass ceiling which has so far denied women the nation's highest office.

After their fierce and drawn-out primaries battle, in which former president Bill Clinton was her chief and staunchest advocate, it was a surprise to many when Obama nominated her as secretary of state.

Some said the Clintons were returning to power through the back door.

But Hillary Clinton, 65, has been steadfastly loyal to Obama, even in many minds taking a bullet for him by assuming responsibility for the deaths of four diplomatic staff in the September 11 attack on the Benghazi mission.

Yet critics say she has failed to accomplish any big signature legacy victories -- such as Henry Kissinger's overture to communist China.

Some blame Obama, who has kept a tight rein on policy on the big issues facing the country -- Afghanistan, Iraq and the Arab Spring. “Clinton has been a loyal, very effective secretary of state, who has used her star power in a useful way for Obama, and has left her mark on minor issues such as the Internet or integrating development policies better into foreign policy,” Justin Vaisse, from the Brookings Institution, told AFP.

“But she has always been dominated, because that's Obama's natural tendency, by a White House which wants to decide on absolutely everything.

“That doesn't take anything away from Clinton. She is truly remarkable, full of energy, intelligent, possessing subtlety and finesse. But the political situation has been such that she has largely been kept on a leash.”Clinton has worked hard, for instance, for a rapprochement with Pakistan -- a key, but wary ally in the war against the Taliban insurgency in Afghanistan -- and knitted together western approval for tighter sanctions against Iran.

During a trip to China this year, she had a successful brush with Cold War style intrigue when Chinese dissident Chen Guangcheng dramatically escaped house arrest and sought asylum in the US embassy in Beijing.

She has also pressed many issues that are traditionally sidelined, such as women's rights -- and in an unconventional move created the State Department's first army of chefs to spread US culinary diplomacy.

But Harvard professor Stephen M. Walt, writing in Foreign Policy magazine, noted a lack of major achievements and argued: “One can't really call her a great secretary at this point, through no fault of her own.”Obama has failed to give her greater authority over foreign policy, Walt wrote earlier this year, and his “initial reliance on a set of 'special envoys' diluted Clinton's clout even more.

“The Pentagon and intelligence community now controls vastly greater resources than the State Department does, and has far more impact on our relations with trouble spots like Central Asia, Yemen, the Persian Gulf.”If Obama wins Tuesday's presidential election, Clinton says she will stay on only until a successor is found. “I'm aiming to leave shortly after the inauguration. That's my plan,” she told The Washington Post recently.

Obama said he would love for her to remain in post, but “despite my begging” she has decided to move on. “I have been on this high wire of national and international politics and leadership for 20 years,” Clinton told Marie Claire magazine recently.

“It has been an absolutely extraordinary personal honor and experience. But I really want to just have my own time back. I want to just be my own person.

I'm looking forward to that.”But of course, if she were to become president in 2016, albeit at age 69, she would have all the authority to be exactly who she wanted to be.