Regulation and antitrust are key elements of government policy. Regulatory and antitrust policies affect virtually all aspects of our lives, ranging from the quality of the air we breathe to the prices we pay for a vast variety of commodities. Regulatory and antitrust policies have undergone substantial change in recent decades. In particular, substantial deregulation has been implemented in several industries, as the forces of competition have been given expanded reign to determine industry outcomes. However, some forms of regulation have expanded, including regulations pertaining to homeland security and the environment.监管和反垄断是政府政策的关键要素。监管和反垄断政策几乎影响到我们生活的方方面面，从我们呼吸的空气质量到我们为各种商品支付的价格。近几十年来，监管和反垄断政策发生了重大变化。特别是，由于竞争力量被赋予了决定行业结果的更大权力，一些行业已经实施了实质性的放松管制。然而，一些形式的监管已经扩大，包括与国土安全和环境有关的监管。