Iraqis are going to the polls to vote on a new constitution. Extra security measures are in place amid fears of insurgent attacks. Some Sunnis fear the proposals may lead to the country’s break-up.Those in Baghdad and towns to the north have spent the night without electricity after a sabotage attack on power lines – not in itself unusual, but a discomfiting reminder of the militants’ reach. For some voters, as in January’s parliamentary election, there will be joy as they smear purple ink on a finger to show they have cast their ballot. For others, there will be fear, as insurgents threaten to kill any who take part in the U.S.-sponsored political process. And some will vote in anger against a draft charter they say gives too much to rival religious and ethnic communities.