If you have a wordpress blog, try the following:
1) Create a new post
2) In the visual editor, start a line with a few spaces followed by some text
3) Click 'Preview', or click to the HTML tab then back to the Visual tab.
You'll notice your leading spaces have disappeared. Begin rant mode. WTF. This is like web dev 101. Just convert them to  's already. But it gets worse. Let's say I decide to work around it and manually add the  's in the HTML editor. Now, switch back to the visual editor. Ahh, leading spaces at last. Let me just switch back to the HTML editor for one last tweak...... #$@!$#% leading spaces are gone again! Unbelievable.
I found one attempt to fix this - unfortunately it's just a bandaid hack and it only works inside shorttags for a specific wordpress plugin.