https://www.change.org/p/yves-guillemot-bring-back-r-u-s-e-onto-the-steam-store

12/8/2015: RUSE is still on the store, available to be purchased for $9.99

12/9/2015: RUSE is no longer available on the store page

Without warning, one of our most favorite WW2 real-time strategy games were removed from the Steam store. This will greatly affect how RUSE and its community will thrive, likely resulting in the game's community slowly leaving the game to die, one user at a time. If the game is put back onto the stores, people can buy the game once more, and continue to have more users come in. Lately, there has been an increase of sales, but with the game's removal from the store page, the game will no longer have new users coming in. This will result in a large boundary between the good and experienced users and the inexperienced and new users.

Update 12/15/2016.

The game will not be coming back to steam sadly.

However you can still purcahse keys for the game on sites like amazon and G2A.

Eugen is soon coming out with a new WW2 RTS so be on the lookout for that.
To all of you who have played RUSE and supported it over the years, Thank you.