"This man is an expert on how to make money in predatory lending and putting him in charge — it is absolutely the opposite of draining the swamp. It is filling the swamp with a swamp monster No. 1 who is an expert on how to take it to low-income families," Merkley said Wednesday on CNBC's "Squawk Alley." "It really is the opposite of what Trump said he was going to do."
The Trump transition team and Mnuchin did not immediately respond to CNBC's request for comment on Merkley's remarks.
Mnuchin, who was finance chairman for Trump's presidential campaign, is a Wall Street veteran, having spent 17 years at Goldman Sachs. His impending nomination seems at odds with Trump's populist campaign rhetoric for downtrodden blue-collar workers.
Some are concerned that Mnuchin would roll back regulations that were drafted in the wake of the Great Recession, such as the Dodd-Frank Act. The former banking executive told CNBC on Wednesday morning that stripping parts of Dodd-Frank "will be the No. 1 priority on the regulatory side." Such legislation was passed with the goal of protecting consumers and preventing another collapse of a major financial institution like Lehman Brothers.
"If you want somebody to dismantle the protections for consumers, he's just the guy to do it," said Merkley, D-Ore., who serves on the Senate Banking, Housing and Urban Affairs Committee.