The Shiite militia commander, slight of build and decked out in green fatigues, views the checkpoint that he oversees as much more than an isolated outpost amid the endless palm groves of the Tigris River valley.
"We are the forward defensive line for Baghdad," said the militiaman, who gave his name as Abu Ali, as he stood with comrades at a battered intersection where the charred remains of shops and a gas station attest to recent combat.
The town of Balad, about 50 miles north of the capital, has emerged as a key bulwark in the defense of Baghdad from Sunni Muslim insurgents allied with the Islamic State, an Al Qaeda breakaway faction.
Just as it was during the U.S.-led occupation, when Balad hosted the largest American military base, Anaconda, the town is a vital supply, communications and logistic hub on the highway from Iraq's capital north toward Sunni strongholds such as Tikrit and Mosul, recently overrun by the Islamic State.
At Balad, the Sunni insurgent rampage down the Tigris has stalled against Iraq's relentless sectarian calculus: Balad, like Baghdad, is overwhelmingly Shiite. Home to an illustrious and resplendent religious shrine, it is the first major Shiite bastion on the road south from Mosul.
Government posters in Baghdad that defiantly proclaim, "They Shall Not Pass" have thus far been validated in this sprawling agricultural market town of perhaps 100,000 residents.
Sunni militants may someday find it possible to infiltrate Baghdad from other areas, or to activate dormant cells in Sunni neighborhoods of the capital. But storming through Balad from the north would surely prove costly for Sunni forces, even before they faced the daunting task of attacking Baghdad, where they would face massive Shiite resistance.
Indeed, the response here to the Shiite religious leadership's call to arms demonstrates its ability to marshal masses of volunteers against takfiris, as Al Qaeda-style Sunni militants are labeled derisively both here and in the Levant nations of Syria and Lebanon.
While government forces scattered in the face of Sunni militants in northern and western Iraq, enthusiastic Shiite militiamen — both novices and battle-hardened veterans of Syria and against the U.S.-led occupation of Iraq — have arrived here and at other frontline areas in large numbers.
In Balad, government forces who were initially routed appear to have reasserted some semblance of control of the critical Baghdad highway — dubbed Main Supply Route Tampa during the U.S.-led occupation and fortified at the time with blast walls, sand barriers and concrete observation posts. The obstacles are now in the service of Iraqi forces, along with the Humvees and other heavy equipment left behind by the Americans.
Still, the situation is tenuous, the battlefield fluid. On Sunday, Sunni militants reportedly stormed into the nearby largely Sunni town of Duluiya, sparking fierce clashes.
Large stretches of the highway from Baghdad to Balad appear nearly abandoned, eerily absent of traffic and subject to deadly attacks. The few motorists tend to hit the accelerator between the many checkpoints. Adding to the sense of uncertainty is the fact that Islamic State activists have posted at least one video online of a fake government checkpoint actually manned by Sunni execution squads decked out as official Iraqi forces.
"They kill you if you are a Sunni working for the government," said one policeman here, who, like others interviewed, did not want his name used because he was not authorized to speak publicly. "And of course if you are a Shiite they kill you no matter what."
Stretches of scorched grass and burned palm trees mark the fierce battles of recent weeks. A number of U.S.-built concrete towers along the highway have been blown up by Sunni militants.
Much of the heavy lifting on the dispersed battle front here appears to be left to the thousands of Shiite militiamen who have answered the religious leaders' fatwa to fight the Sunnis. The various militias' multicolored flags are ubiquitous.
Abu Ali and his charges at the checkpoint adjacent to the main highway are members of the group Hezbollah Brigades, which once fought in Iraq against U.S. forces and is reportedly backed by Iran. (The group is separate from the Lebanon-based Shiite paramilitary and political organization also named Hezbollah.) The sundry militiamen in Balad unanimously exude a sense of bravado and confidence. Whether it is justified on the battlefield is hard to ascertain.
"We have all the help we need: planes, artillery, troops," said one fervent militiaman, from a group called the Vanguard of the Khorasani, a reference to a Shiite site.
At a nearby checkpoint, a Chinese-made pickup truck played Shiite martial ballads. In the rear were several teenage fighters with green headbands, along with one who appeared to be in his 60s, seated in a white plastic chair with his AK-47. They waved at visiting journalists.
Some militiamen here say they have experience fighting in neighboring Syria, where thousands of Iraqi Shiites have battled alongside government forces against Sunni-led insurgents.
"In Iraq and Syria, it's basically the same fight," said a 30-year-old commander of the Hezbollah Brigades who uses the nom de guerre Abu Askar, as he stood outside an abandoned apartment building apparently used as a command post.
Abu Askar, who wore orange-tinted wraparound sunglasses, said he had fought in Syria for almost two years outside Damascus, Aleppo and other locales. With the Islamic State having declared its "caliphate" across the borders of both nations, the two wars seem to be merging. And in Balad, the Iraqi conflict has the feel of a religious war.
"We're getting new recruits all the time," said Abu Askar, his young charges nodding in agreement.
Pickup trucks with militiamen came and went at the compound where Abu Askar and his fighters stood guard.
In daily operations, Shiite militiamen seek out Islamic State militants ensconced in nearby Sunni villages and in palm orchards along the Tigris and its network of irrigation canals. The fighters appear to distinguish little between Al Qaeda-style militants and their allies — Sunni tribesmen and nationalists still angry that the U.S.-led invasion of 2003 upended Iraq's balance of power in favor of the Shiite majority.
"Some people will tell you these are the [Sunni] tribes we are fighting against — that's nonsense," countered one federal police officer. "They're all with Al Qaeda."
A stark contrast to the bluster of the militia members is the wary attitude of Iraqi regular forces. They complain bitterly about a lack of protection against nightly mortar barrages.
"Where are the airplanes?" said one federal policeman stationed at a checkpoint outside town. "Every night from midnight until 3 a.m. we are showered with mortars. We are surrounded here. Am I supposed to fight them all with this?" he asked, thrusting forward his Kalashnikov rifle.
Another officer, who gave his first name as Ahmed, appeared traumatized. He said the image of an infant shot in the head and chest has been lodged in his mind since he saw the slain baby last month during clashes up the road. "I haven't prayed since then," said Ahmed, wearing glasses and a black beret.
Residents interviewed in Balad betrayed no fear of being overrun. A major Shiite tribe, the Guwwam, charged with protecting a nearby shrine, has welcomed the influx of militiamen.
In their view, the townspeople of Balad have no choice but to reject the Al Qaeda-style mind-set that views Shiites as apostates and infidels. They smashed Al Qaeda-linked cells during the civil war of 2006-07, often resorting to brutal means — Shiite death squads were implicated in several massacres, matching their Sunni adversaries in barbarism. Human rights advocates fear that such a cycle of sectarian killing could return.
"We feel secure here," said Ahmed Abdul Hussein, 29, a truck driver who stopped his rig at a vegetable stand. "Al Qaeda has no chance in Balad."
Special correspondent Nabih Bulos contributed to this report.