Sen. John Cornyn, R-Texas, criticized the findings by a government watchdog report that found that the Trump administration had violated federal law in withholding security assistance to Ukraine.
Cornyn said the findings in the Government Accountability Office report are not crimes and do not meet the standards to go forth with impeaching and trying to remove President Trump from office.
"[It's] certainly not a crime and something that no one had ever dreamed in the past would have risen to the level of impeachment," Cornyn said on CBS' "Face the Nation."
"This is the first time in history where a president has been impeached for a non-crime, for events that never occurred, ultimately the investigation never took place and ultimately the aid was delivered," Cornyn added. "This is really unique and I think every senator is going to take this very seriously."
The GAO report found that the Office of Management and Budget broke the law in holding up the aid, which Congress passed less than a year ago, saying “the president is not vested with the power to ignore or amend any such duly enacted law."
The aid in question was held up last summer on orders from Trump, but was released in September after Congress pushed for its release and a whistleblower's complaint about Trump's July call with the Ukrainian leader became public.
The independent agency, which reports to Congress, said OMB violated the Impoundment Control Act by delaying the security assistance for “policy reasons,” rather than technical budgetary needs.
“Faithful execution of the law does not permit the president to substitute his own policy priorities for those that Congress has enacted into law,” wrote the agency's general counsel, Thomas Armstrong, in the report.
Capitol Hill Democrats seized on the report as evidence of a lawless White House, led by Acting Chief of Staff Mick Mulvaney, who is a key figure in the impeachment investigation of Trump.
“The OMB, the White House, the administration broke — I'm saying this — broke the law," said House Speaker Nancy Pelosi, D-Calif.
OMB has argued the hold was appropriate and necessary.
“We disagree with GAO's opinion. OMB uses its apportionment authority to ensure taxpayer dollars are properly spent consistent with the president's priorities and with the law," said OMB spokeswoman Rachel Semmel.
Trump was impeached last month on charges of abusing his power for pressuring Ukraine to investigate Democratic rivals, as he was withholding the aid, and for obstructing Congress' ensuing probe. The Senate will decide whether to convict him on either charge, which would result in his removal from office. A two-thirds vote is required for conviction.
The Associated Press contributed to this report.