She has the experience, the support and an unrivalled fundraising team. Hillary Clinton would make a formidable candidate in 2016, but does she have what it takes to run a presidential campaign?

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They might once have been political rivals, but on Sunday night's 60 Minutes, Barack Obama and Hillary Clinton looked like the closest of friends. The president described her as "one of the finest secretary of states we've had" - praising her stamina, thoughtfulness and discipline.

Mrs Clinton herself would not give much away about her own immediate ambitions. "Obviously the president and I care deeply about what's going to happen for our country in the future. And I don't think ... either he or I can make predictions about what's going to happen tomorrow or the next year."

And yet, there is only one thing anyone wants to know. Will she, won't she, run for president herself in 2016? And, after four years in one of the most gruelling jobs in American government, does she still want the biggest job of all?

One thing is for certain. Hillary Rodham Clinton would be the best prepared presidential candidate in history. No wonder party activists are desperate to see her run. The National Journal took soundings from more than 150 key Democratic party insiders in September last year.

The group they polled ranged from activists to consultants, from elected officials to lobbyists. An overwhelming 70 per cent said they wanted to see her make a pitch for the White House in 2016. It would be a "cakewalk", said one, She has "paid her dues and would be a great leader", enthused another.

In the last few weeks, Mrs Clinton has attracted widespread praise, at the end of her time at the State department; a job which took her to more than 100 countries, racking up almost a million miles.

I would like to see whether I can get untired. Hillary Clinton

Just as importantly, the job has taken her outside the fray of partisan politics, shielding her from the opprobrium surrounding most of Washington's senior figures. Until the accident, that is, and the virus followed by a blood clot which put her out of action for weeks.

Suddenly the headlines changed. Was she too old, too ill, too tired, to plunge back into the relentless, gruelling schedule of a presidential campaign, the almost super-human effort of that two-year long slog, a life lived under the supreme tyranny of polling data?

Hillary herself has made it clear she wants some time off. "I just want to sleep and exercise and travel for fun", the New York Times reports. "And relax. it all sounds so ordinary, but I haven't done it for 20 years. I would like to see whether I can get untired."

For a party which has already won the presidency two terms running, this is some ambition.

But if others have anything to do with it, she will not be resting for long. A valedictory video, produced by supporters to mark the end of her time at State, has been described, not entirely tongue in cheek, as her first political ad of 2016.

Her daughter Chelsea has insisted the blood clot incident will not stand in her mother's way. She told NBC's Today Show that her mother was "exuding the energy, the vibrancy, and certainly the mental accuity that she always has", and would be "healthy and vibrant...for the next 65 years of her life".

California senator Dianne Feinstein came right out there and said it, on CNN. "I would love it if she would run. I think she's accomplished an incredible record. I think she has really unbridled popularity. She has a total knowledge of all the issues."

Polls apart

There is no doubt that Hillary Clinton enjoys almost unparalleled popularity, with no shortage of evidence to back up the figures. Psephological guru Nate Silver, of the fivethirtyeight blog, describes her as "the most polled about American in history, other than those who have actually become president".

He has carefully charted her favourable and unfavourable ratings, going back to 1992, along with the key moments in her political career. But, he concludes, the huge peaks and troughs could be seen as a result of the amount of criticism she was subjected to, by her opponents and the news media.

Yet although Mrs Clinton has managed a few years away from the tawdry stuff of everyday politics, she has proved her ability not just to withstand scandals and criticism, but to bounce back. And there is nothing Washington loves more than a comeback - as husband Bill might concur.

Of course any political campaign, let alone one for the presidency, is as much about logistics as mere likeability. We already know, pace Obama himself, that Hillary is "likeable enough".

What she has, that no other putative candidate has, is a formidable machine. This month the organisation that ran her 2008 presidential bid paid off its debts in full, although tellingly, the account remains open, with more than $200,000 cash in hand.

A winning machine

The website, www.hillaryclinton.com remains online, although without the 'Hillary for President' memorabilia it once sold. And the Clintons - Washington's ultimate power couple - have some of the Democratic party's most generous and influential backers on speed dial.

Bill Clinton certainly threw himself into Obama's 2012 campaign with astonishing vigour, drawing huge crowds, and rousing ovations whenever he mentioned Hillary's name. As campaigner-in-chief, there might be none better.

And for many, it is simply time to break through those 18 million cracks in the glass ceiling once and for all: another chance to make political history. As Emily's List president Stephanie Schriock told the Daily Beast: "It's time to have a woman in the White House ... there would be massive energy surrounding a Clinton presidential campaign."

Tellingly, the very idea of a Clinton candidacy has got conservatives worried. One political action group has already started a fundraising drive, proclaiming: "The time to start planning for the defeat of Hillary Clinton is now."

Just think of those key constituencies: women, young people, urban professionals, Latinos and African Americans, uniting behind a Hillary flag. Mrs Clinton might be yearning for a bit of time to relax. Destiny, and the political imperative, might not let her rest for long.

Felicity Spector writes about US politics for Channel 4 News

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