A world in which the powerful have no secrets is an inestimably better world.
If you know something you wish the world knew, give it to WikiLeaks.
If you have money you can spare, give it to WikiLeaks.
Their current featured video is horrifying: it's from the guncam of an Apache, with audio of the crew's radio conversation, as they circle a group of journalists and talk themselves into mowing them down with a chaingun: while the guncam resolution is perhaps too poor to make a clear distinction between the victim's large SLR and an RPG, the crew choose to fire repeatedly, including telling their superiors specific information about the "weapons" the targets are carrying that are not remotely evident from the video, despite strong behavioral evidence that the journalists are harmless—most of the party are carrying nothing, none show signs of agitation or watchfulness at the helicopter very close by.
When a van arrives to pick up the sole, badly wounded survivor, they open fire again, destroying the van and killing all inside.
Why we need WikiLeaks:
The Pentagon has kept this video secret for past three years, despite FOIA requests from Reuters.
If this is what it takes when employees of a multi-billion-dollar British corporation are the victims, how often does this kind of thing happen and go unreported?
I could maybe sit still for an argument that the kids in the helicopter are not war criminals: in a war zone full of civilians, they took in ambiguous information and interpreted it consistently in the wrong way because they were keyed up and wanted to shoot, but it reads as manslaughter as much as cold-blooded murder. (Maybe they're not war criminals, in other words, but just fools who can't be trusted with guns and should spend the rest of their lives trying to make up for what they have done.)
What I can't even begin to swallow is the cover-up: in the absolute best case, this is a fuck-up, and it needs to go on people's records and lead to a review of procedures. The officials who decided to hide it, and every single one who makes a similar decision, need to be drummed out of government service and never let back into a position of trust.
Why WikiLeaks needs defending:
Because WikiLeaks reveals information like this, the DoD has planned to attack them [PDF] by intimidating their sources.
Here is the timeline of the incident, and below is the shorter (18-minute) version of the video.
A Redditor claiming to be a former cavalry scout working in the same general area says this is commonplace and defends it somewhat.