Tea party-backed Sen. Rand Paul (R-KY) on Sunday warned President Barack Obama that he was in danger of "losing the moral authority to lead this nation" because the Internal Revenue Service (IRS) unfairly scrutinized the tax-exempt status of conservative groups.

"I don't know if people were targeted for conservative religious values or just conservative political values, and sometimes there's an overlap," Paul told ABC's Martha Raddatz, adding that the IRS scandal, last year's terrorist attacks in Benghazi and the news that some journalists were investigated for national security leaks were all taking away from "the president's moral authority to lead the nation."

"Nobody questions his legal authority," the Kentucky Republican explained. "But I think he's really losing the moral authority to lead this nation. And he really needs to put a stop to this."

"If no one is fired over this, I really think it's going to be trouble for him trying lead in the next four years," Paul added.

The president announced earlier this month, that Treasury Secretary Jack Lew had asked for and received a letter of resignation from Steven Miller, the IRS acting commissioner.

Watch this video from ABC's This Week, broadcast May 26, 2013.