Seventeen Senate Democrats joined with every Republican in voting to roll back some bank rules.

Many of those Democrats did so as they push for political survival.

The Senate voted 67 to 31 on Wednesday to ease regulations on all but the largest banks, in what would become the biggest rewrite of financial laws since the Dodd-Frank reform act passed after the global financial crisis. The legislation would raise the level at which banks are considered "systemically important" and exempts smaller banks from other rules aiming to curb risky behavior.

Critics objected to a provision raising the threshold for an institution to be considered "too big to fail" to $250 billion in assets from $50 billion in assets, arguing it opens taxpayers up to more potential liability should a mid-sized institution fail. Under the bill, the entities below $250 billion in assets would no longer have to go through a "stress test" to prove they can survive a crisis. Some Democrats also criticized a provision related to mortgage data that they say will make it harder for the government to target discriminatory or predatory lenders.

It is unclear if the GOP-majority House will seek to pass the legislation or a more drastic rollback of bank rules that Senate Democrats would be reluctant to support.

The bank legislation left Democrats balancing competing concerns as they battle for control of Congress in November. Some members of the party have long argued smaller banks and lenders in rural areas should face fewer restrictions. Several Senate Democrats like Heidi Heitkamp of North Dakota face re-election in November in states President Donald Trump won in 2016 and have tried to create an appearance of supporting bipartisan or moderate policies.