What happened at the Boston Marathon was inconceivable, horrific, shocking to most who have seen the videos and photos, but there are lots of Americans for whom the scene was appallingly familiar: veterans of the wars in Iraq and Afghanistan. I spoke to five men who served with my husband in the infantry. All of them went to Iraq at least once between 2006 and 2009 and are now scattered across the country, integrating into civilian life, more or less. They're my friends.

It wasn't like seeing the Iraq war break out on the Boston streets, they said, but they found their experiences rushing back while watching the news as they tried to figure out what kind of bomb it might have been. Because, for a year or more of their adult lives, what happened on Monday was a regular experience. Some worried the attack could become another pretense for war. Some tried to stifle a feeling that Americans don't care about the people overseas who are blown up all the time.

On Monday, T.J. Brummett came home from his construction job in Indiana and flipped on the TV just a few minutes after the explosion. He knew immediately it wasn't an accident. Brummett was an Army specialist deployed to Baghdad in 2006 and 2007, and for a few months, he was a driver for an Explosive Ordnance Disposal unit, or EOD, the guys who blow up bombs -- you probably saw them in The Hurt Locker. He was on call 24 hours a day, and "when someone was blown up, it was my job to get them there."

Brummett watched the news replaying the explosion over and over. "When C4 explodes it has a crack. It doesn't sound like anything else." The bombs in Boston didn't sound like that. This was more "gunpowderish," Brummett says. (The Washington Post reported Tuesday night that some investigators think black gunpowder might have been used because the blasts were not strong enough to cause structural damage to buildings or gouge the sidewalk.) "Probably had a timer," he said. (An official told The New York Times an egg timer was used.) Nick Cox, a former Army specialist who deployed to Iraq twice, saw the white smoke and figured it was the work of an "amateur." (Wired reports the white smoke indicates the explosive was gunpowder.) Of the bomb made of a pressure cooker, Staff Sgt. John Sellars thought, "Wow, that's some OIF-2 shit right there," referring to the military's term for the second year of combat operations in Iraq. "Ball-bearing IEDs would do a number on the old-school Humvees," Sellars said. "Then we started up-armoring everything… so that generation of IED wasn't any good anymore." In Iraq, the American armor and insurgents' weapons were constantly evolving. That hasn't happened in America, of course.

"It was a little weird, actually," said David Warnock, a former sergeant who went to Iraq twice and whose sister lives in Boston. He's now going to school at Ohio State. On Monday afternoon, "I was just doing some restorative yoga. So I was like, really mellow when I got out, and I had a series of text messages asking about my sister without any context."

"I went through some weird stages," Warnock said. "At first, just, like, shock and anger -- how could this happen here? Then I guess I realized I'm sort of surprised it doesn't happen more. Then I was like, I just read on the BBC there was another wave of bombings in Iraq that killed like 40 civilians. And I paused to reflect on the paradoxical situation that I would be so shocked and outraged over what happened in a city that my sister lived in but not a country I once tried to help."

The news "instantly" brought back memories of Iraq, Brummett says. "I've been walking around all day thinking about it… It's not even so much an American thing. It's a human thing... Because I was there. It wasn't any less dramatic to me, watching it happen to another race of people than it was to see it happen to white people in America… It's not an American thing. It's terrible this happens anywhere in the world."

That's what bothered Sellars, now stationed in Fort Hood, Texas, about the media frenzy after the marathon bombing. "Every time something like this happens, I find myself angry," Sellars said. "Not that someone would do that on American soil, but that Americans react the way they do… Because we have this attitude that that can't happen here -- bombings are something that happens in Third World shitholes." (Or as Politico quoted Tom Brokaw on Tuesday: "We're the most advanced nation in the world, living with Third World vulnerabilities.") This bombing was so small compared to some things he saw in Iraq. The bombing in Boston, while awful, "is nothing like six artillery shells in the back of a car," Sellars said, referring to an IED set off in front of a mosque after Friday prayers in 2007. That was "carnage." He saw a photo of the 78-year-old marathon runner getting knocked down by the blast. He felt for the guy, but, "He should count himself as fortunate."

Warnock understands the shock. "I know what it feels like to be hit by a bomb and to have pieces of it in you," he says. "Certainly I would be surprised if I were to be hit by an IED in Columbus." But, someone left a backpack in his college's student union Tuesday. Police closed off a few city blocks and part of the campus, and then detonated the backpack. "I think that kind of reaction is just kind of insane." 

TV's endless replaying of the explosion bothered Cox. It was "sensationalist," Cox said, and exploitative. "I know what a frickin bomb looks like, I don't need the media to explain it to me. I don't need to be reminded of it." 

"You put it away, but you don't really turn it off, either," he said of his experiences in Iraq. "And then you come home and you bring all this stuff with you and you don't let it go. Something like this happens, it's like a light switch, it turns it on… I don't have a whole heck of a lot of civilian friends I can talk to about it."

For some, the attacks stirred up a nervousness that they would have to go back. They worried that if the attackers were foreign, it would be used as a pretext for military action. "I've got four months left on inactive reserve," Brummett said, referring to the time after active duty when you can technically be recalled if the military needs more soldiers. "I don't want to have to go to Afghanistan... or North Korea." Greg, a former sergeant who went to Iraq twice and now is in college in Pennsylvania, explained, "I'm mostly worried about any U.S. retaliation. I think that's where the source of the sinking feeling in my gut lies: I'm afraid of another war."

No one complained that an IED at home was being treated differently than an IED in a war zone. Of course a war and a marathon are different. Of course a rare thing and an unfortunately common thing are different. But, Warnock said, "There is always something of that bitterness, and it's something that I work to dispel, to not be bitter and angry. There is something to the fact that there wasn't this outrage" when people died in Iraq, he said. "Imagine if there was this media response to every IED that killed an American soldier. So there is this kind of like, 'Well, there were a lot of Americans who died in bomb blasts.'  But at the same time, it's not that hard to understand it was American civilians on American soil. People don't expect marathon runners to get blown up…. Somewhere inside that does offend."

Warnock added, "There are still soldiers in Afghanistan being killed and it's not in the news cycle. I try not to lose myself in that bitterness. I'm a civilian now so I might as well start thinking like it."

(Above, a member of the National Guard Joint Task Force Empire Shield stands guard in Grand Central Station in New York the day after the Boston Marathon bombing.)