feuse of its devstting eets in utions nd other mehnismsD ollusion is prohiited nd leglly proseutedF etD olluders hve lwys existedD nd my ontinue to existF e thus rise the following question for mehnism designX What desiderata are achievable, and by what type of mechanisms, when any set of players who wish to collude are free to do so without any restrictions on the way in which they cooperate and coordinate their actions? sn response to this question we put forwrd nd exemplify the notion of collusion-leveraging mechanism. sn esseneD this is mehnism ligning its desidert with the inentives of ll its plyersD inluding olludersD to signint nd mutully eneil extentF yf ourse suh mehnisms my exist only for suitle desidertF sn unrestrited omintoril utionsD where lssil mehnisms essentilly gurntee H soil welfre nd H revenue in the presene of just two olludersD we prove tht it is possile for ollusionEleverging mehnisms to gurntee tht the sum of soil welfre nd revenue is lwys highD even when ll...