There is a new generation of trade agreements, of economic agreements like the bold new Trans-Pacific Partnership Agreement (TPPA), that have many of us less than excited, concerned instead about their vast potential to handcuff elected governments and give corporations more power.

It is hard to trust anything created with such locked-box secrecy, such sneering disregard for the views and interests of the hundreds of millions people it will impact. Only the faithful and the foolish blindly trust that the powerful, when secreted in rooms together, will prioritize the needs of the powerless.

As a physician, it is the threat to our right to protect ourselves, the increasing limits on what governments are allowed to do to defend our health that agitate me the most. It is the large sums of lawyer money that will be needed to defend every public health measure that impacts someone's bottom line.

According to leaked drafts, the TPPA expands the use of the Investor State Dispute Mechanism, already a growing favourite of corporations under other agreements, which allows commercial interests to directly challenge the democratic decisions that governments make. Disputes are decided by tribunals of international investment lawyers who innocently rotate between representing companies and being the judges themselves. Few if any have public health training. And the parties can ask for tribunals to deliberate in secret, like the TPPA negotiations themselves.

Tobacco experts have led the way in flashlighting the potential negative health impacts of the TPPA. They have pushed for specific exemptions for tobacco laws, shelter from the hard rain that tobacco companies and their law firms can bring. Tobacco is special the experts say, an especially bad product, and because of the particular evil that tobacco companies practice, these experts believe the companies shouldn't have the privilege of challenging our public health laws for their own interests.

No tobacco control advocate wants to see new avenues for challenging tobacco taxes, marketing restrictions, packaging laws. Already, Philip Morris, the world's largest tobacco company, is pounding Australia for its first-of-its-kind plain packaging laws, using Australia's trade agreement with Hong Kong as hammer. Philip Morris is looking for billions of dollars in compensation for the money they say they will lose because of plain packaging (in case you had any doubt whether plain packaging will work).

Even if they lose, Philip Morris knows that kind of intimidation, its chill effect, is worth the price. Tobacco companies believe in prevention too -- an ounce of prevention, they know, is worth pounds and pounds of money.

But why only tobacco? Drinking alcohol is the third leading cause of death and disability in the world. Don't alcohol regulations deserve just as much protection? Should we really allow the undermining of policies that help reduce drunk-driving deaths, decrease alcohol-related assaults and injuries, prevent breast cancer and cirrhosis of the liver?

And prescription drugs? Pharmaceuticals are one of the fastest rising costs to health care systems around the world, threatening the ability to provide universal care. Should we really be offering drug companies new ways of interfering with public formularies, government purchasing and other strategies that reduce costs and encourage the rational use of cost-effective medications?

And as nations are just starting to get their heads around how to solve the obesity crisis, surely we shouldn't dump everything out of our toolbox before the real work has even started. We need to keep our public policy options open, to make room for initiatives to clean up a food environment that is literally killing us.

Emptying the toolbox is exactly what corporations have in mind of course, to leave us with as few moves as possible, to smother David in his cradle before he can grow up and take on Goliath. Yes, there is a legitimate interest in reducing "technical barriers to trade," challenging countries who use public policy for ulterior trade motives, to favor their own companies, but the TPPA and other economic agreements like the Trans-Atlantic Free Trade Agreement look to be giant oversteps.

Investor-state regimes hand corporations the keys, bolstering the already formidable influence they wield in domestic arenas. They give transnationals too much power to stop health regulation that might hurt their revenue, health regulation badly needed amidst a worldwide epidemic of obesity and tobacco and alcohol-related disease.

The Trans-Pacific Partnership alone includes almost 800 million people in 12 countries, an economic zone controlling almost 40 per cent of the world's GDP. Negotiated under the flag of creating jobs, increasing wealth, there will be little opportunity to oppose the harmful parts of the accord once the lawyers have climbed into their BMWs and gone home. Transparency and a true civil society discussion is needed now, as the TPPA will surely have a substantial impact on our health and well-being.

ALSO ON HUFFPOST: