At last, the Obama administration seems to have reached a tentative deal with its negotiating partners on the Trans-Pacific Partnership, the landmark Pacific Rim trade treaty that far exceeds NAFTA in size, scope, and, well, corporatism. Covering 40 percent of the world's economy, the TPP makes the regulatory regimes of its 12 (mostly Asian) member nations part of one big happy family. In substantial part, it does so by making it easier to do business for familiar corporate heavyweights like Apple and Pfizer. But it also lets foreign corporations sue the U.S. in non-U.S. courts. And it doesn't explicitly prevent foreign governments from manipulating their currencies in ways that Wall Streeters often happen to be better than the rest of us at profiting from.

The disagreements over the TPP's provisions are nuanced and complex. But the theme is not. Indeed, the TPP could well be President Obama's most enduring legacy, because it gives his corporatism its biggest stage yet. It captures the central idea of his presidency — that when big government and big business make policy, the result is good for average Americans, even if it reduces their political freedom, or even their political participation. ObamaCare laid that marker down domestically, triggering a lightning round of health industry consolidation that turned the "big five" insurers — and their $346 billion yearly revenues — into a "big three." The math is simple: When everyone has to buy the products dominant corporations sell, dominant corporations win. From a liberals' standpoint, TPP takes the idea global — allowing powerful international corporations to further disadvantage American workers through a complex set of legal, financial, and economic privileges. As Rep. Rosa DeLauro (D-Conn.) put it: "The administration has put big business first, [and] workers, communities, and small businesses last."

And for once, the left doesn't know what to do about it.

The administration has long been able to get liberals to support just about anything if it panders enough to the base's brand of identity politics. (The same has happened on the right for generations.) So, as long as Obama appeased the left's social-justice sensibility, he has been able to focus on advancing his corporatist agenda — what The New Republic senior editor Noam Scheiber rather obliquely termed "boardroom liberalism."

"It's a worldview that's steeped in social progressivism, in the values of tolerance and diversity," Scheiber wrote. "The picture of the boardroom liberal is a corporate CEO handing a refrigerator-sized check to the head of a charity at a celebrity golf tournament. All the better if they're surrounded by minority children and struggling moms."

The TPP takes that strategy to its logical conclusion, promising the most fabulous gains for the people who had the least influence over its creation. It's as if anything philanthropy can do, ultra-elite inside deals can do better. "Big win for U.S. workers," the White House recently tweeted. "@POTUS just secured a trade deal that helps the middle class."

But here, the boardroom liberal president has lost the liberal base. Because that tweet is just about word for word the opposite of what labor unions, movement progressives, and old-school liberals believe about the TPP. Spluttering and frightened, they've all begun unloading on the president. And they're having an effect. For fear of insulting the base, Hillary Clinton — whose surname is all but synonymous with the Democrats' pro-corporate reboot — seems ready to break with Obama on the TPP.

The TPP might not pass. Congress must approve it. And Democratic senators from Elizabeth Warren to Bernie Sanders have huge objections. "In the Senate, I will do all that I can to defeat this agreement," Sanders has thundered. "We need trade policies that benefit American workers and consumers, not just the CEOs of large multinational corporations."

In the same breath that Sanders slammed the TPP for rewarding corporatists first, he also warned that the treaty would follow in the footsteps of previous deals that "cost millions of jobs and shuttered tens of thousands of factories across the United States." In his mind — and according to the ideology of the anti-corporate left — policies that lavish perks and privilege on the power elite just can't be good, on balance, for the rest of us peons. According to the moral intuition of Sanders and Co., the best regime — the most just — simply can't be one that keeps the power elite in clover. President Obama begs to disagree. And with the TPP, he's one step closer to hardwiring his worldview into the Democratic Party.

Republicans, for once, have it easy. They know the TPP is America's best shot at ensuring that international trade remains dollar-denominated for decades to come. Desperate for a grand strategy sound enough to replace mere "toughness," the GOP could do much worse than that.

For Democrats, it's devilishly more complicated. With Clinton hanging in the balance and Biden waiting in the wings, TPP is their sharpest reminder yet of how much is at stake in choosing Obama's successor. The next party leader will likely determine whether the consecration of corporatism becomes the left's secular religion — and, so, under Democratic rule, the government's.