Antitrust: Lynchpin or folly?

Economists generally agree that US antitrust policy is complex, changing over time, divided among several US federal government agencies, and subject to frequent court reversals. The underlying question remains whether the US needs more or less regulation of market structures.  Key questions are: 

• Are US markets becoming less competitive because of mergers and acquisitions? • Are US markets becoming more competitive because of new technology? • Are US markets becoming more or less competitive because of globalization? • Is enough information available for wise antitrust enforcement? 

US Federal agencies involved in antitrust include: 

US Federal Trade Commission at: http://www.ftc.gov US Department of Justice: http://www.usdoj.gov/atr/index.html 

For international perspectives:   http://www.justice.gov/atr/public/international/index.html 

For analysis see: 

For a strong anti-regulatory position see Heritage Foundation, a private advocacy group. It has been influential in arguing against antitrust enforcement.  For an overview see: http://www.heritage.org 

See also the Cato Institute: http://www.cato.org and the American Enterprise Institute:  http://http://www.aei.org 

For a strong pro-regulatory position see: Public Citizen at: http://www.citizen.org/ 

The Brookings Institution attempts a non-partisan position and publishes frequent overviews of antitrust law. See, for example: http://www.brookings.edu/about/press 

Please read the above question,  answer it in 300 words, and add  1 reference with IN-text Citation.