After sabotaging power lines, insurgents knocked out water lines across the Baghdad area on the eve of Saturday's landmark vote on a constitution aimed at defining democracy in a nation once ruled by Saddam Hussein. Water also ran out in homes in some parts of the capital and water pressure waned in others as tanks ran out. Power appeared to be returning slowly to the capital. The blackout was not expected to affect Saturday's balloting as paper ballots were being used, not machines, though electricity officials could not say if power would be back completely before polls open. The sabotage signaled the insurgents were looking to mar the referendum even amid a heavy country-wide clampdown by US and Iraqi forces. However, there were no reports of suicide bombings or any of the other major attacks that insurgents carry out regularly, suggesting they had been hampered by the security measures.