A protest outside the hotel where the Trans-Pacific Partnership ministerial meetings were held in Atlanta last year. (Tami Chappell/Reuters)

The proceedings began with little fanfare, on the first floor of a nondescript government building in Southwest Washington.

Inside the International Trade Commission headquarters, there was no shouting, interrupting or grandstanding, only a civil — if a bit wonky — back-and-forth on non-tariff trade barriers, economic models and trade deficits.

In short, the hearings were a far cry from the normal legislative wrangling carried out on C-Span or by lobbyists in the inner sanctums of lawmakers’ Capitol Hill offices.

Yet the obscure commission holds sway over one of the most contentious political issues of 2016: the Trans-Pacific Partnership, or TPP, struck between the United States and 11 Pacific Rim nations.

With a vote in Congress unlikely until after the November elections, the entire influence industry seems to be whirring either for or against the trade deal, with a slew of business groups endorsing it and environmental and labor interests opposing it.

But for now, Congress is not the only target of lobbyist entreaties. Instead, advocates and foes are appealing to the ITC in order to influence its report on the deal’s economic impact, which the commission hopes to produce by May 18. Lawmakers will use the report’s findings to bolster their arguments, while the White House — if the report is favorable to its views — will use it to sell the pact to wavering members.

“The ITC’s report in this case is going to be very influential,” said Eric Emerson, an international trade attorney at the law firm Steptoe, who is not representing groups testifying before the ITC about the deal.

“There will be a lot of interest groups on each side, a lot of argument as to whether the agreement is a net plus or net minus for the country, particularly from the employment perspective. Having the ITC, which is about as independent as it gets in terms of an executive branch agency, come out and say, ‘Here’s the net impact on the U.S. economy,’ — assuming they come out in a positive way, and I suspect they will — I think that’s going to be a very important talking point for the administration.”

For three consecutive days recently, in eight-minute segments spanning nine hours each day, lobbyists for some of the nation’s biggest corporations, labor unions and trade groups testified before the panel of six appointed bureaucrats.

They included lobbyists for Walmart and Gap, who praised the deal for lowering tariffs on beef, cheese, pencil cases and cotton sweaters.Leaders of the U.S. Chamber of Commerce and the National Association of Manufacturers framed the pact as a chance for U.S. companies to sell more goods abroad. Representatives for the AFL-CIO, United Steelworkers and other unions urged the commission to consider the deal’s potential to erode labor conditions and wages.

An independent quasi-judicial agency, the ITC doesn’t take political or policy positions on trade deals. Its commissioners are regarded more like judges and aren’t lobbied in the same manner as lawmakers. 

Commissioners are nominated by the president and confirmed by the Senate to serve nine-year terms. The panel is made up of three Democrats and three Republicans, including Chairwomanman Meredith Broadbent, a Republican nominated by President Obama in 2011.

In 2015, more than 9,200 companies, groups and other entities lobbied the House and 9,100 lobbied the Senate. More than 800 lobbied the Environmental Protection Agency. By comparison, just 54 lobbied the ITC, according to the Center for Responsive Politics.

But its report on the TPP is nonetheless influential. The commission is charged with investigating the likely impact of the TPP on the U.S. economy and specific industries. It will calculate the estimated impact on gross domestic product, exports and imports, employment opportunities, and U.S. consumers.

While the report is not the only economic analysis of the TPP, it is considered the most authoritative, unbiased and official. Fast-track legislation requires the ITC to send the report to Congress and the president.