Tax rules don’t just collect money—they also push people toward (or away from) certain behaviors. If you’re a U.S. person (an individual or a company) and you help enforce an international boycott the U.S. does not support, or you pay a bribe to a foreign official, the tax code fights back. It strips away valuable tax benefits and denies deductions, making these activities far more expensive than they first appear. This chapter explains exactly how those penalties work.