trough and bribe-givers open themselves up to blackmail”); Daniel Kaufmann and Shang-Jin Wei, Does “Grease Money” Speed Up the Wheels of Commerce? 2 (Nat'l Bureau of Econ. Research, Working Paper No. 7093, 1999), available at http ://www.nber.org/ papers/w7093.pdf (“Contrary to the ‘efficient grease’ theory, we find 104 HOUSE_