When Hillary Clinton visited Ireland last month she clearly enjoyed being back among friends but it was also obvious that she was extremely tired. It was put down to her exhausting schedule as US Secretary of State. But as we now know there was far more to it than that.
Mrs Clinton left hospital on Wednesday and her doctors expect her to recover completely after treating a blood clot in her head, and as one of Ireland's best friends we must hope that will be the case. More and more questions are being raised, however, about what impact her health will have on her political future and if it will influence a decision whether to run for the US presidency in 2016.
Mrs Clinton had been admitted to hospital last Sunday for treatment of the clot which it is said could have stemmed from concussion earlier in December when she fainted while at home battling a stomach virus and fell, striking her head.
Doctors found the clot, located in a vein that runs through the space between the brain and the skull behind the right ear, and administered blood thinners. They emphasised she didn't suffer a stroke and there was no neurological damage. Political fallout may be a different matter.
There is never a good time for anyone to get ill, but in Mrs Clinton's case the fact that her illness has emerged well before any decision on the 2016 race is a big plus for her.
It would be wrong to underestimate Hillary Clinton. I met her a number of times while working in Washington and have followed her career closely. She is one of the toughest, most astute political operators in Washington and she doesn't give up. Now that she's out of hospital, I imagine she will follow her original plan once she steps down shortly as Secretary of State: rest for a while and then take the political pulse of the country and decide by the middle of next year whether to run.
When she comes to make a decision she will also have the unique advantage of knowing exactly how gruelling presidential campaigns are, no matter how healthy you are. She's been through two of her husband's campaigns and, of course, her own exhausting marathon in 2008 before bowing out and paving the way for Obama's victory. Democrats admired her for that. And now Americans admire her more than any other woman in the world, according to a Gallup poll on Monday – the 17th time in 20 years that Mrs Clinton has claimed that title. And a recent ABC News/' Washington Post' poll found that 57pc of Americans would support Mrs Clinton as a candidate for president in 2016, with just 37pc opposed.
Much then depends on her recovery over the course of the year. This isn't the first time Mrs Clinton has suffered a blood clot. In 1998, midway through her husband's second term as president, she was in New York fundraising for the mid-term elections when a swollen right foot led her doctor to diagnose a clot in her knee requiring immediate treatment. But there is a difference between being ill at 51 and at 65. I have no doubt that Hillary Clinton could overcome the age issue in a presidential bid but age coupled with suggestions of ill-health would be a much tougher, though not insurmountable, combination.
There is no such thing as perfect health, as previous White House occupants are well aware. Bill Clinton had successful bypass surgery in 2004. Dick Cheney had major heart problems when he was George Bush's vice president and it isn't uncommon for presidential candidates' health and age to be an issue. In both the 2000 and 2008 races, Senator John McCain had to rebut concerns he was too old to be commander in chief or that his skin cancer could resurface.
On December 14, 2001, President Bush had four non-cancerous skin lesions removed from his face. I remember reporters learned of this only when Bush appeared before cameras with dark red spots on his face. A month later, on January 13, 2002, he briefly lost consciousness while sitting on a couch in the White House, watching a football game. His head hit the floor, resulting in an abrasion on his left cheekbone and a small bruise on his lower lip. The incident was blamed on a combination of not feeling well in previous days and having a problem eating a pretzel though no satisfactory medical explanation was given.
Six months later, Bush underwent a colonoscopy at Camp David. He denied signs or symptoms of colorectal cancer and said he had the procedure to be "super-cautious" about his health. However, before the 20-minute procedure, he had to invoke section 3 of the 25th Amendment, temporarily transferring presidential powers to Vice President Cheney – the first time an official transfer of power had been made under that provision of the Constitution.
One thing is certain: Hillary Clinton is above all a born political fighter. She has overturned all the odds before by becoming the first ever first lady to win a US Senate seat, make a presidential bid and then go on to become one of America's most successful top diplomats. It's been a gruelling decade. Rest, away from the cauldron of Washington and the world's trouble spots, may work wonders for her health. Regardless of politics, let's hope it does.