Sen. Elizabeth Warren is not backing down in her battle with President Barack Obama over the Trans-Pacific Partnership, a massive, 12-country trade deal that has divided the Democratic Party and triggered a volley of critical statements between the Massachusetts Democrat and the commander-in-chief.

‘The history of these agreements betrays a harsh truth.’ Sen. Elizabeth Warren (D-MA)

“The history of these agreements betrays a harsh truth: that the actual enforcement of labor provisions of past U.S. [free trade agreements] lags far behind the promises,” the report claims. “This analysis by the staff of Sen. Warren reveals that despite decades of nearly identical promises, the United States repeatedly fails to enforce or adopts unenforceable labor standards in free trade agreements.”

RELATED: Democrats wage civil war over trade deal

I’ve joined @SenatorHeitkamp, @Sen_JoeManchin, & 12 other senators on an amdt: No Fast Track on any deal with ISDS: http://t.co/2wTmOt5oMh — Elizabeth Warren (@SenWarren) May 18, 2015 Broken Promises: Decades of Failure to Enforce Labor Standards in Free Trade Agreements,” takes the United States to task for consistently failing to enforce labor protections in its trade deals, and points to ongoing labor-related human rights abuses in 11 of the 20 countries with which the U.S. currently has free trade agreements. “The TPP is being hailed as the strongest free trade agreement yet. But this is not the first time this claim has been made,” the report concludes, seeking to undermine Obama’s claim that TPP would be “the most progressive trade bill in history.”

Obama, who is pushing Congress to approve so-called “fast-track” authorization for the trade deal, which he is still negotiating with 11 South American and Pacific Rim countries, has called liberal critics of the agreement “just wrong.”

“They’re making this stuff up,” Obama said earlier this month in response to Warren, who has said the TPP would make it easier for corporations to ship jobs abroad and could allow Wall Street to weaken provisions in the Dodd-Frank financial reform law. “This is just not true.”

RELATED: Obama on Elizabeth Warren: It’s not personal

The president later emphasized that his disagreement with Warren “has never been personal,” as the rift grows between pro-trade Democrats and the party’s progressive wing, threatening to spill out into the 2016 election. Hillary Clinton, the Democratic Party’s heir apparent to the presidential nomination, has avoided taking a stand either way on the trade issue as the intra-party conflagration continues.