What does U2 really know about war?

I've got soul but I'm not a soldier

Here's some songs which suggest U2 have some views about the effect of war...

GNR once asked in a song 'what's so civil about war anyway?'

U2 seem to write songs with lyrics about war in some form or another on just about every album they've released.

Except for Boy, that album was just full of stories....ahem.

U2's lyrical references to war heated up with the release of U2's first truly 'popular' album War. Marking Bono's ascent into a true lyrical monster, War's songs features thoughts on soldiers shooting protesting civilians in Sunday Bloody Sunday. 'Seconds' reflects on terrorist actions in trying to set off atomic bombs (a theme U2 often turn to) in a supposed attempt to cause nuclear war.
Maybe.

Maybe they just want us all to give peace a chance.

Winter

A song probably taken from the No Line on the Horizon album recording sessions, Winter was used in the soundtrack for the Wim Wenders film. Brothers (U2 have a long association with Wim - he directed their video for Stay and Until the End of the World was used for the film of the same name). Winter is about is a song about the experience of the armed forces in Afghanistan, where Winder's film is set.

The Unforgettable Fire

Inspired by paintings that were about the nuclear bombs that were dropped on the two Japanese cities, Hiroshima and Nagasaki to effectively end Japan's involvement in World War II, the Unforgettable Fire is a reflection not on war but the last effect of the atomic bombs had on the people of Japan.

Bullet the Blue Sky

Arguably the most political song U2 has ever written, at least it's probably the most popular one! The lyrics are a savage indictment on American foreign policy.

Miss Sarejevo from Original Soundtracks Vol 1.

Please don't let them kill us...

When Bono asks if there's a time for East 17 (a boy band that everyone has now forgotten) during the Bosnian war, you've gotta ask what he's talking about.

The song's lyrics actually praise the rebellious spirit of the Sarajevan people who refused to surrender their way of life during the conflict.

And what did they do? They staged a beauty contest.

This clearly inspired the chorus of the song, "Here she comes, heads turn around, here she comes, to take her crown".

Please

If you could consider that the IRA's disgraceful and disgusting campaign against the people of Ireland was a civil war of sorts then Please is U2 exhorting Ireland's Political leaders to stop the civil war they have been waging.

Mothers of the Disappeared 

Is a lyrical expression of the suffering experienced by the mothers and grandmothers of the thousands of children abducted during the conflict in Central America from the late 1970s through to the mid-1980s, particularly during Argentina's so-called "Dirty War" (1976-1983).

The Dirty war was a civil-style war that the American government covertly sanctioned in a bid to stop the 'communist threat' that was pervading at the time. Given this song was written in the mid-80s one can see how it's a cousin of sorts to Bullet the Blue Sky - indeed both songs appeared on the Joshua Tree album.