The former Maryland congressman has plowed his personal fortune into a long-shot presidential run.
It may be a preview of the run-up to the 2020 presidential election.
Lawmakers have passed a bill to roll back regulations adopted after the 2008 financial crisis.
The Trump administration is headed to court over its attempt to override the process for naming a new head of the Consumer Finance Protection Bureau.
The move sets up a critical battle over who will keep banks in line.