Is John Kerry another Henry Kissinger or James Baker? Both are recognized as greats of American diplomacy whose names and achievements still resonate in the annals of the 20th century.
Some now say that, as Kerry marks his first anniversary in office, he too may be on track to earn a place in America's small pantheon of great secretaries of state.
From Iran, to Syria to the Middle East peace process, the former senator has waded into the murkiest, most intractable global issues that his "rock star" predecessor Hillary Clinton largely avoided.
Sworn in on February 1, 2013, Kerry's arrival at the State Department was a kind of homecoming for the son of an American diplomat who declared "foreign service is in my genes" as he brandished a dog-eared diplomatic passport issued when he was just 11.
The first anniversary of his tenure falls with Kerry once again overseas, this time in Germany.
But he can look back on some 320,961 miles (516,500 kilometers) traveled to around 39 countries, with 149 days already spent on the road.
"Secretary Kerry could not feel more privileged to be doing this job for this president in a very complicated world," a State Department official told AFP.
But the now 70-year-old, whose shock of grey hair is the only clue to his age, says he's not ready to start trumpeting any achievements.
Kerry "has issued a department-wide edict against anyone wasting time counting accomplishments or accepting failure," said the official, who is close to the secretary.
"As he likes to say, 'foreign policy doesn't have exit polls.'"
Juggling tough issues
And despite the odds, Kerry seems to be winning respect for his persistence in bringing hardened foes together.
"We have a very positive appreciation of John Kerry's efforts," said a Western diplomat, who asked not to be named.
"In all the current crises, he represents the most positive kind of American interventionism, in the best sense of the term."
The diplomat paid tribute to Kerry's "courage and daring" in all the dossiers that he is currently juggling, adding that "without Kerry, there would surely have been no resumption of the peace talks."
Indeed, the greatest criticism of Kerry recently has come from Israeli and Palestinian officials irked as he pushes them toward painful compromises to seal a Middle East peace deal.
His quest has been denounced as naive, obsessive and even messianic.
Even his long-time friend, Republican Senator John McCain, has attacked Kerry over the US administration's cautious Syria policy, calling him "a human wrecking ball."
Kerry's small team of staff privately acknowledges the attacks have stung, but hit back that it's always easier to criticize when you're not on the sharp end of policy-making.
The top US diplomat "fundamentally believes in diplomacy... and to his credit, he has put himself directly in the middle of the mix," said Aaron David Miller, who worked with six secretaries of state.
And Miller noted that, unlike in his first term, President Barack Obama, "who cares much more about the middle class than the Middle East," has been forced to delegate on foreign policy.
While the September deal with Russia to rein in Syria's chemical weapons and a November interim accord with Iran to roll back its nuclear program are significant achievements, they remain incomplete.
"The full story has yet to be written. These things can all go south easily. Not because of his efforts, but because of the nature of the problem itself," Miller said.
To win his place in the secretaries of state hall of fame, Kerry "has to accomplish something quite consequential and he's not there yet," the Woodrow Wilson Center scholar added.
Kissinger negotiated three disengagement accords between Israel, Egypt and Syria in the early 1970s, helped seal the landmark 1979 Israel-Egypt peace accord and set up America's outreach to China.
Baker played a key role in German reunification and the Madrid peace process.
Catnaps and guitar
"I think on most of the crucial questions, the jury is still out," agreed Hussein Ibish, a senior fellow at the American Task Force on Palestine.
Kerry "has been incredibly energetic and taken on some very, very difficult challenges with a personal intensity that was not fully expected," Ibish added.
Like Clinton before him, Kerry has kept up a grueling pace, leaving staff half his age struggling to keep up.
The Vietnam veteran says "every day is extra," the State Department official said.
"He also relies on long bike rides, grandchildren, and the occasional power catnap to keep him fresh."
And an essential item that accompanies him on every trip is his guitar, to help him wind down after a stressful negotiating session.
Analysts are also impressed Kerry has been so willing to put himself out on a limb, despite the high risk of failure.
"The fact that he works with only a small circle around him is an issue that could become an internal problem," confided the Western diplomat.
"He was alone for months on the peace process."