As the U.S. approaches the tenth anniversary of the 2008 financial meltdown, it faces a massive test of the post-crisis regulatory apparatus—thanks in no small part to Democrats in Congress.

A deregulatory bill, S.2155, introduced by Republican Senator Mike Crapo of Idaho, chairman of the Senate Banking Committee, proposes a major rollback of the 2010 Dodd-Frank Act. Dubbed The Economic Growth, Regulatory Relief, and Consumer Protection Act, it cruised through the committee in January. Although there are several elements to the bill, the most eye-popping provision is a significant shift in which banks are considered “systemically important” and thus subjected to greater oversight and tighter rules. Currently, banks with $50 billion in assets fall into that category. The proposal would move the threshold to $250 billion—a 500 percent jump that would erase the mandate of enhanced scrutiny for 25 of the 38 largest banks in the country.

The measure’s framework is expected to eventually pass the Senate thanks to a dozen finance-friendly and swing-state Democrats who have openly announced their co-sponsorship. With Republicans in control of the House, the bill seems destined to reach President Donald Trump’s desk this year.

Despite the vocal opposition of more liberal colleagues such as Senators Elizabeth Warren of Massachusetts and Sherrod Brown of Ohio, the bill’s leading Democratic co-sponsors expect it to be debated as soon as next week, according to a senior Senate aide involved in the process. The intra-party debate regarding the regulatory rollback is giving new insight into the battle for the direction and identity of the party ahead of this year’s midterms, hardening a divide between those who would move the party left to energize the base as well as populist independents and those attempting to appease more conservative voters and the party’s deep-pocketed donors.

Many progressive activists, led by the anti-corruption organization Rootstrikers, have taken to calling the Democratic co-sponsors the #bailoutcaucus. Nine of the twelve Democrats supporting the deregulatory measure count the financial industry as either their biggest or second-biggest donor, according to an analysis of Federal Election Commission data listed by The Center for Responsive Politics.