WASHINGTON — In New Zealand on Thursday, U.S. Trade Representative Michael Froman is set to sign the Trans-Pacific Partnership, a free-trade agreement among 12 countries in Asia and North and South America. President Obama now has at least 30 days to submit the TPP to Congress for a vote.

Ever since TPP negotiations started, I have been worried by its possible consequences for our state. My concerns only grew when the text was finally released last fall. Rest assured, I plan to vote against the TPP when it comes up for a vote, and here are a few reasons why.

To begin with, I strongly disagree with the closed-door process that led to this agreement. Negotiations took place in secret with a total lack of transparency. Members of Congress and the public were left in the dark about its details until a short time ago and weren’t given a chance to voice feedback. Instead, U.S. negotiators relied on advisers from some of the largest corporations in the country.

Moreover, Congress has passed legislation to “fast track” the agreement. This means that it will get only an up-or-down vote, with limited debate and no opportunity to offer amendments. I strongly opposed the fast track legislation and can’t believe Congress consented to being a rubber stamp for an agreement that has so many implications for our constituents.

My fear is that Maine will suffer the same ill effects we have under the North American Free Trade Agreement – but on a much larger scale. The TPP would be the largest free-trade agreement in U.S. history; some have called it “NAFTA on steroids.”

After 20 years under NAFTA, you’d be hard pressed to find many in Maine who think our state benefited from that agreement. Since it was signed, the U.S. trade deficit has increased and Maine has lost many good-paying jobs – especially in manufacturing – both to foreign competition and to corporations sending jobs to lower-paying countries.

This trend would continue under TPP. A prime example is that the agreement lifts tariffs on athletic shoes made in Vietnam – threatening the future of American manufacturer New Balance and the hundreds of people it employs in Maine.

I’m certainly not opposed to trade, and I applaud Maine businesses that export their products overseas. But the TPP doesn’t do enough to establish an equal playing field for them. Other countries in the agreement don’t have the rigorous labor, environmental or food-safety standards that we do in the United States. The TPP does little to raise the bar for those countries, placing American jobs at a disadvantage.

But one of my biggest concerns with the TPP is that it could actually lower those standards in the United States. In a recent case under NAFTA, Canada and Mexico argued that country-of-origin labeling laws on beef and pork in the U.S. place their products at a competitive disadvantage.

The World Trade Organization sided with these two countries, threatening heavy tariffs on U.S. products if the labels were not removed. Although I was strongly opposed, Congress voted to repeal these common-sense regulations to avoid the penalty.

Even worse, the TPP gives private corporations the right to sue governments over regulations that they think are barriers to trade. These disputes aren’t settled in court, by the way, but by a panel of trade attorneys.

This kind of process threatens the sovereignty of our government and hamstrings our ability to respond to emerging issues and the will of our people. Members of Congress should be making decisions based on their benefit to the people they represent – not out of fear of how foreign corporations will react.

So-called free-trade agreements come at a cost. While multinational companies are poised to reap the benefits of the TPP, American workers, consumers and citizens will be the ones to foot the bill. For these reasons, and many more, I will be voting against it.