A top Senate Republican argued this weekend that President Trump’s interim pick to run the Consumer Financial Protection Bureau, not the outgoing director’s choice, will be in charge Monday morning amid a growing partisan standoff over the controversial agency.

Agency Director Richard Cordray, in resigning Friday, effectively made Chief of Staff Leandra English acting director. That set up a fight with the Trump White House, which later Friday named Mick Mulvaney, director of the Office of Management and Budget, as interim director.

“I think Mick Mulvaney will be in charge,” South Dakota GOP Sen. John Thune, a member of Senate Republican leadership, told “Fox News Sunday.”

Thune argued the Justice Department supports the president’s position and that the agency has “very little accountability” and “really no oversight to Congress.”

“It’s an agency that needs to be reformed,” he told Fox. “So I expect that Mick Mulvaney will be on the job and be calling the shots over there.”

He suggested that Trump hastily announced a permanent replacement whom the Republican-controlled Congress can promptly confirm, though he acknowledged that the courts might ultimately have to decide the issue.

“We'll process [the nomination] as quickly as we can in the Senate and get somebody installed as soon as possible,” he said. “That ultimately is the best way to resolve this.”

Cordray, a Democrat, in fact named English deputy director before resigning, so she would become acting director when he quit.

Cordray and the White House have cited different laws to support their positions. Administration officials on Saturday acknowledged that some other laws appear to clash with the one they cited, said that in this case the president's authority takes precedence.

The consumer watchdog agency has enmeshed in partisan politics since its creation after the 2008 financial crisis.

Cordray was an Obama appointee often criticized by banks and congressional Republicans as being too aggressive.

The CFPB was proposed by now-Sen. Elizabeth Warren, D-Mass., in her previous job at Harvard Law School, and it was created as part of the laws passed following the 2008 financial crisis and subsequent recession.

Under Cordray, the first CFPB director, the agency implemented or proposed myriad new rules and regulations for the banking industry. Nearly every American who deals with banks or a credit card company or has a mortgage has been affected by rules the agency put in place.

Facing Republican opposition, former President Barack Obama had used a congressional recess appointment to install Cordray to lead the agency. When Trump was elected, Cordray became one of the highest-level political appointees to remain, and some congressional Republicans had urged Trump to fire him.

Cordray announced this month that he planned to resign his office by the end of November. Many thought his early resignation would give Trump a chance to appoint his own director, who could remake the agency and potentially roll back the protections Cordray and his staff put into place.

House Minority Leader Nancy Pelosi, the chamber’s top Democrat, said Sunday that federal law makes clear English serves as acting director until the Senate confirms a permanent one.

“All Americans should be deeply concerned about the White House’s cynical decision to flout the law and attempt to put the ringleader of its dangerous, anti-consumer protection policies in charge of the CFPB,” said Pelosi, of California. “Democrats will be firm in defending the rightful appointment of Leandra English as acting director.”

The Associated Press contributed to this report.