Has anyone noticed that Iraq, supposedly transformed into an oasis of peace and tranquility by George W. Bush’s troop surge, is growing less peaceful and tranquil by the day?The nation’s attention has been riveted by the presidential campaign, with its compelling characters and its edge-of-your-seat story line. Iraq is treated almost as a theoretical issue: What would happen there if Barack Obama became president, as opposed to what would happen if Hillary Clinton became president, as opposed to what would happen if John McCain became president? There has been little debate about what’s happening in Iraq right now.That seems likely to change.The past several weeks have seen a recrudescence of the kind of horrifying, spectacular violence that the Decider’s surge was supposed to have ended.Last Thursday, two massive bombs hit a shopping district in the Shiite-dominated Karada neighborhood of Baghdad, killing 68 people and injuring more than 120. That atrocity followed twin car-bomb explosions earlier in the week that killed 24 people and wounded 56 elsewhere in the city.On Monday came what was described as the worst attack on U.S. forces in months. According to Iraqi police, a suicide bomber approached an American patrol in Baghdad and detonated his explosives, killing five soldiers and injuring three others. U.S. military officials confirmed the deaths but did not immediately give details of the incident.Also on Monday, a female suicide bomber in Diyala province blew herself up at the home of a Sunni clan leader who had been cooperating with U.S. forces against al-Qaida. Sheik Thaeir Ghadhban al-Karkhi was killed, along with his 5-year-old niece, an adult cousin and a security guard.Two days earlier, in an orchard near the banks of the Diyala River, Iraqi police announced they had found a mass grave with the decomposed remains of between 50 and 100 people, some of them children. It was unclear who the victims were, or who had killed them.When the Bush administration celebrates a 60 percent reduction in overall violence in Iraq, it’s easy to forget that this is compared with June 2007, when the sectarian civil war was raging and bombings with scores of victims were a regular occurrence. The surge managed only to reduce the level of violence from apocalyptic to agonizing — and now even those gains seem to be slipping.Bush’s surge was designed to give the Iraqi government the necessary breathing space for Shiites, Sunnis and Kurds to reach vital compromises. President Jalal Talabani and Prime Minister Nouri al-Maliki showed their gratitude earlier this month by rolling out the red carpet, literally, for Iranian President Mahmoud Ahmadinejad.Bush’s Middle East policy is designed largely to blunt the influence of Iran, which seeks a dominant role in the region. So it must have been galling to the White House to watch as Ahmadinejad swept into Baghdad in a ceremonial motorcade and toured the city with great fanfare. Never one to miss a chance to stick in the needle, Ahmadinejad questioned the motives of those who “visit this country in a stealth manner.”He was referring to the fact that Bush has to fly unannounced into Iraq and can stay only for a few hours. It would be far too dangerous to let citizens know in advance that their liberator was coming to see to their welfare.So violence seems to be creeping back, the Iraqi government is showcasing its developing friendship with Iran, and, oh yes, these achievements are costing American taxpayers around $12 billion a month, according to a new book by Nobel Prize-winning economist Joseph Stiglitz and co-author Linda Bilmes. The authors estimate that by 2017, the wars in Iraq and Afghanistan will cost the nation between $1.7 trillion and $2.7 trillion.The Congressional Budget Office projects a somewhat lower cost, estimating that, by 2017, the two wars will have consumed between $1.2 trillion and $1.7 trillion. Still, not what you would call chump change.I’m not aware of any educated guess at how much it might cost if the occupation of Iraq were to last 100 years, as McCain has suggested.It is unclear whether the recent increase in violence in Iraq is temporary or the beginning of a new and tragic cycle. It’s hard to imagine a return to the level of carnage of a year ago, since by now many of Baghdad’s neighborhoods have been ethnically cleansed. But all of us — even the presidential candidates — had better pay attention.Send Eugene Robinson e-mail at email@example.com.