One of the biggest challenges for me to understand politics in the United States is getting a grip on how much influence lobbyists exert on everything from legislation, public opinion and news media to rhetoric by politicians.

That task has become ever more daunting given that the lobbying industry has become increasingly pervasive and has continued to grow even during the economic downturn, from $3.30 billion in 2008 to $3.51 billion in 2010, according to the Center for Responsive Politics (CRP).

The number of active federal lobbyists is close to 13,000, and that does not include the vast army of lobbyists at the state level. Just a few months ago when the 12-person bipartisan Super Committee in the US Congress tried to work out a $1.5 trillion federal budget cut over the next 10 years, news in Washington was that the health and defense industries were readying for a battle with their lobbyists.

The defense industry spent $1.2 billion on lobbying from 1998 to 2010, and that amount does not include campaign contributions from the industry, according to the CRP.

The powerful defense industry lobby is one of the reasons it is so hard to cut the US defense budget, which is now higher than it was during the Cold War, and why there is constant noise about China's military buildup, the threat from China, indeed the threats from everywhere, despite the fact that the US has an unrivalled military capacity and its military spending exceeds the next top 10 countries combined.

From 2001 to 2010, US military spending increased by 81 percent and accounted for 43 percent of the global total, according to the Stockholm International Peace Research Institute.

Clearly, fear-mongering is the best way for defense industry lobbyists to convince lawmakers to keep the monstrous military budget while the country is facing funding cuts in education and healthcare.

The powerful influence of the lobbyists can also be felt in many China-US trade and investment disputes, everything from anti-dumping charges to some discriminative assessment of Chinese direct investment in the US such as in cases regarding Huawei Technologies and China National Offshore Oil Corp in their acquisition bids. CRP data reveal that communications, energy and resources, along with finance, health and labor unions, are among the biggest spenders on lobbying.

An inside story of the K Street in Washington DC, where many lobbying firms assemble, might help people who are not familiar with the process understand how many decisions on Capitol Hill are made.

In his latest book Capitol Punishment: The Hard Truth About Washington Corruption From America's Most Notorious Lobbyist, Jack Abramoff, one of the most prominent American lobbyists, revealed that at one time he had a great deal of influence in some 100 Congressional offices, but he considered this a failure at the time because there were still hundreds of Congressional offices where he wanted more influence.

Released last year after serving three years and six months of a six-year sentence for bribery of public officials, fraud and other crimes, Abramoff said he is thinking of writing another book "An Idiot's Guide to Buying a Congressman". He said the best way is to tell a capable Congressional staff member that they will offer him a job after he leaves the Capitol Hill. "The moment we said that, we owned him," he said.

The truth is that if you look at the top lobby firms in Washington DC, many are staffed by former government officials and members of the Congress or staff members working on Capitol Hill.

Abramoff believes that new ethics regulations introduced on Capitol Hill still leave plenty of loopholes for lobbyists to explore.

Next time when the US does its China bashing - whether it's on currency manipulation, cyber attacks or Chinese direct investment in the US - we must find out which lobbyists are behind it.

The author, based in New York, is deputy editor of China Daily US Edition. Email: chenweihua@chinadaily.com.cn