Leading article: The lack of bloodshed alone is a good sign

But if the supporters of the referendum have to hold their breath for a province-by-province breakdown of the voting, they can draw comfort already from the unexpectedly peaceable nature of the referendum. Of course, the level of violence would be unacceptable in a normal democracy. Rockets were fired yesterday into Baghdad's green zone, five soldiers were killed by a roadside bomb in Ramadi, in western Iraq, and at least one civilian was killed and others injured while voting in Baghdad.

But Iraq is not a normal democracy, and the level of violence at the weekend was nothing compared to the bloodshed during January's elections to a constituent assembly. Then, hard-line Sunni opponents of the vote tried to terrorise their fellow Sunnis from taking part in a process they deemed tainted by association with the American-led occupation.

The fact that Sunni terror groups largely abstained from such heavy-handed tactics at the weekend suggests they realised many Sunnis were going to vote, so that bombing polling stations would result in killing "their own".

There is a broader message here, which is that even the outraged and alienated Sunnis are acclimatising to the unfamiliar workings of a political process and to the realisation that ballots can be more effective than bombs or guns in solving grievances. In that sense, it would not be a disaster if enough Sunnis voted "no" to ensure the constitution failed. The outcome would remind sceptical Sunnis that large minorities can use the democratic system to block changes they oppose.

For sure, the whole process of writing a constitution would then go back to the committee stage. But, in their understandable itchiness to get free of the Iraq incubus, the Americans encouraged the authors of the constitution to offer many concessions to Iraq's Shias and Kurds. If the draft of the constitution were to be rectified to meet some, but not all of, the Sunni objections, that would be no bad thing.

The lesson of the referendum is that Iraq may be heading at last towards political, rather than armed, battles - slugging it out in elections rather than in the streets. If so, that offers hope of an exit strategy for the troops occupying the country, which is something most of us would like to see as soon as possible.