There are several separate wars going on in Iraq. There are still a few groups of Sunni Arab terrorists going after Shia civilians. But most of the action has shifted to leaders. Shia terrorists target Sunni Arab leaders, believing them most responsible for the terror since 2003, and for supporting Saddam before that. Up north, the struggle for Mosul and Kirkuk (and the nearby oil) has Arabs and Kurds battling each other. Because of the January 31st elections, there are some attacks on campaign workers and officials. For some Iraqis, these elections are, literally, war. These elections will determine who will run provincial government.
But police are finding that it's not always so obvious who, or what, caused each terror attack. There are enough police now to actually investigate each terror incident, and often the culprit turns out to be common criminals (extortion is a big money maker, and you need enforcers) or family feuds (six years of violence has stirred up a lot of bad blood in families, clans and tribes). That ill-will is being worked out via bombings and shootings that, to the outsider, look like more terrorism. It is, but Islamic radicals are not the cause.
Nevertheless, the violence level continues to be down 90 percent versus the peak years of 2005-7. Most of the bad guys are dead or in exile, and the remainder are mostly being hunted down by Iraqi security forces. American troops find explosions or shootings pretty rare. For many combat troops, one incident a week is about all they get, versus several a day the last time they were here (a year or two ago.) The troops looking for action, seek ways to get to Afghanistan.
With Saddam and the Sunni Arab dictatorship gone, Iraq has to face a new set of problems. In the south, there is a struggle between many Shia Arab parties for control of the area where most of the oil is. Political attitudes range from very religious, and pro-Iranian (but few to the extent that they would welcome an Iranian annexation of the south) to secular. In central Iraq, the Sunni Arab minority is still a problem, and will remain one for years. Not just the terrorists, but the many criminal gangs. The worst of these got their start when Saddam was in power, and worked with government protection for many years (and served as a secret police auxiliary in return). The gangs will not go away easily. Up north, the conflict is between Kurds and Arabs (both Sunni and Shia). The Kurds claim more territory then they currently occupy. This could lead to some major fighting, if not resolved peacefully.