US President Barack Obama's handling of the Arab spring is likely to crop up when he debates foreign policy with Republican Mitt Romney in their final presidential debate, scheduled for this morning, Hong Kong time.
But what the United States could have done differently as long-time allies were knocked from power in one country after another is far from clear, foreign policy analysts say.
What is clear, the experts say, is that whoever serves the next four years as president must realise that there's no appetite for the United States' old paternalistic stance toward Arab nations; new leaders demand a more respectful and balanced relationship similar to what Turkey or European nations enjoy.
"One thing that has sunken in is that American leverage is limited," said Nathan Brown, a political science professor at George Washington University.
There were high-stakes moments in each revolt in which the Obama administration had to pick sides, and in all but the failed uprising in Bahrain, where the US Navy's Fifth Fleet is based, the United States allied itself with Arab protesters.
One place where support came very quickly was Syria, with the memorable scene of then-ambassador to Syria Robert Ford taking a risky ride into the flashpoint city of Hama, where protesters greeted him with flowers. But as the conflict grinds on and Syrian public opinion of the US sours, the Obama administration appears hamstrung.
The loose weapons, outlaw militias and extremists in Libya offers a cautionary tale in arming rebel movements or leading a military intervention. The elections in Tunisia and Egypt that swept the Muslim Brotherhood to power similarly give pause as the US determines whom to back among the Syrian opposition.
Facing such grim options, Obama and Romney offer similar plans in the Syrian crisis: continue non-lethal and humanitarian assistance, lean on opposition forces to form a transitional government, weaken the regime through sanctions and allow Arab allies to arm the rebels.
Neither campaign speaks about the United States directly arming the rebels now. Romney has said the US should identify fighters who "share our values."
Egypt is another key laboratory for US policy.
After some wavering in the beginning, the Obama administration sided with the protesters. But Egyptians clearly haven't forgiven the US for backing Hosni Mubarak for nearly three decades. Protesters lobbed tomatoes and insults at Secretary of State Hillary Clinton on a recent visit, and polls show that a majority of Egyptians reject financial aid from the US government.
In a bitter irony for the Obama administration, Libya, the Arab nation where US popularity was once highest, is now its Achilles' heel on foreign policy.
The death of the US ambassador in the September attacks on US posts shined a light on the worst of Libya since the fall of Muammar Gaddafi: weak central government, little in the way of law enforcement, and a wide-open space for jihadists to plot and carry out attacks.