When the North American Free Trade Agreement (NAFTA) was signed 20 years ago, there were many promises of how it would create jobs for United States workers, strengthen our trade balance and lower prices for consumers.

Unfortunately, those promises have not come to pass, but some of our worst fears have. In Maine, it has severely weakened manufacturing and has led to the loss of thousands of good-paying jobs. And across the country it has contributed to growing income inequality by benefiting large companies at the expense of workers and consumers.

After all that, our country still imports more than we export by about $40 billion. With NAFTA's track record, I’m very concerned about two pending agreements that could have even more wide-ranging impacts — the Trans-Atlantic Trade and Investment Partnership (TTIP) with the European Union, and another with Asian countries, the Trans Pacific Partnership (TPP).

As with NAFTA, these agreements aren’t as simple as removing tariffs to encourage trade. Modern free trade agreements aim at removing other kinds of “barriers.” These can include laws and regulations that ensure proper working conditions, a clean environment, safe food and products, and fair competition, among other things. In the past, these agreements have resulted in a race to the bottom on rules for workers, consumers and the environment. They have also made it easier for large companies to send manufacturing jobs overseas, where fewer regulations and lower wages cut their costs.

The specifics of a trade agreement can even trump our own laws. In disputes, investors can sue states and countries for violation of trade agreements when they enact stronger regulations that could cut into future profits. For example, under NAFTA, a Canadian mining company sued for $50 million after the State of California passed a law requiring companies to backfill open pit mines after completing operations. What’s more, the disputes aren’t settled in public court, but by a tribunal of international trade lawyers.

Little information has emerged about the agreements currently in negotiation, but what has come out is troubling. Draft language of the TPP’s environmental language leaves key terms like “environmental laws” up to interpretation. Without teeth, it includes no methods for imposing penalties on countries that violate those vague terms.

With such wide-ranging implications, it’s clear that we need to give trade agreements the utmost review and careful consideration before entering into them, if we do so at all. But so far, we have not been allowed to do so. Negotiations have happened behind closed doors, with heavy input from large corporations and almost no consultation from Congress. Moreover, legislation has just been introduced to rubber-stamp these agreements through Congress.

The Constitution gives Congress the exclusive authority to set the terms of trade. In the past, though, Congress has given the Executive Branch “Fast Track” authority to negotiate trade agreements without its oversight. Once an agreement has been finalized under Fast Track, Congress only has a limited time to debate it and cannot make any amendments.

The Executive Branch’s Fast Track authority expired in 2007, but a bill was just introduced to renew it. I am deeply worried about losing the opportunity to review and consider how these agreements could affect our protections and economy. In October, I joined over 150 members of the House of Representatives in sending a letter to the Administration asking that Congress be fully engaged in the final approval process of these agreements.

“Twentieth Century ‘Fast Track’ is simply not appropriate for 21st Century agreements and must be replaced,” the letter reads. “The United States cannot afford another trade agreement that replicates the mistakes of the past. We can and must do better.”

Don’t get me wrong, I place great value on policies to expand foreign markets for U.S. goods and think Maine companies should have access to the global marketplace. But we need to make sure that these trade agreements will actually help that happen without weakening our economy in ways that NAFTA has or lowering the bar for workers and the environment.

I strongly believe that the Congress should retain its Constitutional authority, and I will continue pushing for the opportunity to weigh the policy issues contained in these agreements.