Unshaken by the latest surge in violence, Iraqis braved the threat of bombs and attacks to vote Wednesday in key elections for a new parliament amid a massive security operation as the country slides deeper into sectarian strife. Hundreds of thousands of troops and police fanned out to guard voting centers in the first nationwide balloting since the 2011 American pullout. Scattered attacks still took place north of Baghdad, killing at least three people and wounding 16. Prime Minister Nouri...