The full story of what happened in Syria's third-largest city on the eve of Ramadan is still unknown, but it looks like one of the bloodiest days of Bashar Al Assad's 11-year rule, and of the protests against his regime which will soon enter their fifth month.
The timing of this assault is no surprise. That forces loyal to Mr Al Assad attempted to decimate the opposition in Hama ahead of Ramadan is an indication that the regime recognises this will be its most testing four weeks.
The Arab Spring is about to run into an unpredictable obstacle, in the form of the Muslim holy month. With the uprisings in Syria, Libya and Yemen still unresolved, changes in the next four weeks could prove decisive.
In Syria, sending tanks and troops into Hama, a bastion of conservative Muslim opinion, on the eve of Ramadan was designed to end the uprising before the holy month begins, or else so strangle it that it dies out over the long, hot month.
Mr Al Assad's forces may calculate that if they can strike a serious, overwhelming blow against the opposition before Ramadan, they can then bargain with a severely weakened opposition under the auspices of the holy month.
Since Ramadan is traditionally the time when the authorities are merciful and release prisoners or commute sentences, this would give them a propaganda victory while defeating or severely weakening the rebellion.
Until the dust settles over Hama, it won't be clear if the protesters will be cowed. The likelihood is not: they have previously braved the army's worst brutality with no outside help, in full knowledge of what might happen to them.
Mr Al Assad wanted to end the uprising before Ramadan because the month is doubly bad for him: it will boost the protesters while reducing his room for manoeuvre.
During Ramadan the mosques will be filled with people, increasing the likelihood of demonstrations. At the same time, the Syrian people, some of them still ambivalent about the uprising, would be disgusted at the sight of protesters being attacked during or soon after prayers. The wider Arab and Muslim worlds would also find such images abhorrent.
This is a particular concern for Syria, where the political and military leadership are of the Alawite religious sect, a minority ruling a Sunni-majority country. Any attempt to attack protesters around mosques, or at all during the holy month, may be read by some as anti-Islamic. This could sow the seeds of sectarian violence.
The logistics of Ramadan falling in summer will also have an effect. After breaking their fast in the early evening Syrians may return to the mosque for Taraweeh prayers late at night. Such gatherings are difficult to police, because the security agencies cannot bar people from the mosques. And they can last until the early hours, when Muslims will gather to eat ahead of the day's fast.
That means there are legitimate ways for protesters to gather late into the night. This presents a difficult scenario for those trying to constrain protests and gatherings.
The same applies to Yemen, where President Ali Abdullah Saleh trip to Saudi Arabia for medical treatment created a vacuum that sucked much of the momentum out of the protest movement. In a message on Sunday, he called for dialogue and reconciliation.
In Yemen, as in Syria, there is a strong chance the daily gatherings will reignite protests. At the same time, however, Ramadan limits the protesters' ability to manoeuvre politically - there is a strong bias towards showing mercy and reconciliation during the month, and Mr Saleh's message suggests he intends to capitalise on that.
The opposite may hold true in Libya. The long, hot month of Ramadan favours Colonel Muammar Qaddafi, sitting tight in Tripoli, supplying the city's population with food and water.
By contrast the rebels, always tenuously cohesive and tending to gravitate towards their own cities and regions, will be stretched by the month of fasting. Refraining from eating and drinking during daylight hours will severely limit the fighting ability of the rebels in desert conditions.
The rebels' international supporters also face a Ramadan dilemma. Just as Bashar Al Assad must consider the public reaction in the wider Muslim world, so must the Libyan rebels' friends consider the optics of raining bombs down on Libyans.
Nato and its allies are wary of this while at the same time concerned Qaddafi loyalists could use any lull to press their advantage; hence the signals from France and Qatar that military action will continue.
The recent murder of the rebels' army commander Abdel Fatah Younis will only exacerbate tensions. The combination of infighting among the rebels, the difficulty of making military advances during Ramadan, and Nato's caution could mean the uprising suffers severe setbacks, or worse, during Ramadan.
The Arab Spring is now the Arab summer and has run into Ramadan. The peace and reflection Muslims search for during this time will be in short supply amid tumultuous times, and there is no telling what the most important events in recent Arab history will look like by the end of the Muslim holy month.
