All trade deals are driven by some form of bribery. That is their product, their purpose.
Even Trump's new trade deals, while better, are just more of the same.
It's always a matter of what interest - be it a single company, a whole industry, a particular union, or unions generally - is willing to supply something of value to the politicians in charge. That value can be plain old bribes, campaign cash or other political support - volunteers and such.
The Clinton/Bush groups, seeing the decline of big unions in America, tilted the machine toward big business and especially the globalism of Wall Street. Exhibit A - the replacement of GNP with GDP. They ignored the blue collar workers of the American "rust belt" of Pennsylvania, Ohio, Illinois, Indiana, Michigan, Wisconsin, and the like, including coal country - turning to the export of heavy industry. Greens loved it. Wall Street financed it. Whole factories were torn down and shipped to the third world.
That class of voter, blue collar, used to be reliable Democrat and they were courted by Democrats. The Clintons and Obama took them for granted; old loyalties/voting habits die hard so they were shat upon for nearly thirty years. Trump saw the opportunity; played to it, and took enough of those states' electoral votes by narrow margins.
Trump's trade policy is not motivated by that same ol' corrupt big business/big labor bribery; rather, his policy is driven by votes. He bought votes with a new trade policy. That said, his trade negotiators still sell favors. Negotiations are still secret. Checks are still being written, just by different interests. The old, established interests are shut out; they hate losing and having to beg for just some of their long held privileges. The cracks run along new, different lines. The old trade constituencies are fractured.
The irony of it all is that the Republicans, who championed "free trade" from the late '40s on, now, in the form of Trump, may have returned to their roots as the party of the tariff. They were the tariff party throughout the 19th century and that stance can even be traced back into the pro-tariff Federalists of the late 18th century.