Edited sentence: Federal DEA, Customs, and Immigration agents all "happen to be" at the tribal "sobriety" checkpoint, where tribal and federal officers demand that drivers open their car trunks, allow their passenger compartment to be searched, produce identification, and submit to a radio check for outstanding warrants.In August 2009, Nation officers lost a court case over these practices.The Nation has been harassing at least one Kitt Peak employee, stopping his car without cause.The Tohono O'odham tribal police sometimes operate unconstitutional roadblocks along the state highways that cross their Nation.The tribal and federal agencies collaborate, each claiming responsibility for what they think they are immune for, both seeking to evade responsibility.These checkpoints sometimes provide local cover for Federal checkpoints that do suspicionless searches for identity, drugs, weapons, and undocumented aliens