Supreme Commander 2, Chris Taylor's RTS follow-up to 2007's Supreme Commander, will be using Valve's Steamworks program for its DRM. All copies of Supreme Commander 2, digitally obtained or purchased in out-dated box form, will require an installation of Steam for validation.
Additionally, a demo of the title is now available for download through Steam ahead of the game's March 2, 2010 release date. Give it a try and if you like it go ahead and pre-order it on Steam. You'll save yourself $5. The Xbox 360 version is set to release on March 18, 2010.