When it comes to business regulation in Washington, Mercatus, Latin for market, has become the most important think tank you've never heard of. Staffed by veterans of the White House office that reviews and often scales back proposed rules, Mercatus, with its free-market philosophy, has become a kind of shadow regulatory authority. The White House's top regulator, John Graham, was briefly a member of Mercatus's board of advisers before taking the government post. Many well-known independent Washington think tanks, such as the Brookings Institution or the American Enterprise Institute, issue analyses of regulations, but usually only on broad themes or prominent issues. Industry lobbyists -- representing, say, auto makers or drug companies -- circulate views on more obscure regulations, but with the specific purpose of boosting their sponsors' profits. Mercatus is a rare hybrid. It is considered an independent think tank because it's part of George Mason University and gets funding from many sources. But Mercatus issues biting opinions on dozens of rules, including little-known ones that only lobbyists usually get excited about. "Mercatus is the only academically respectable place I know that does what K Street lobbyists do," says Peter Van Doren, editor of Regulation magazine, a journal published by the libertarian Cato Institute. "They follow the minutiae of regulation to see how rules will affect particular industries." - online.wsj.com