"I am writing to ask you suspend all efforts surrounding your ‘impeachment inquiry’ until transparent and equitable rules and procedures are established to govern the inquiry, as is customary," McCarthy wrote.
McCarthy pointed out that Pelosi has given no clear indication as to how the impeachment inquiry will proceed, including whether key historical precedents or basic standards of due process will be observed.
"The swiftness and recklessness with which you have proceeded has already resulted in committee chairs attempting to limit minority participation in interviews, calling into question the integrity of such an inquiry," McCarthy said.
The scandal, which resulted in impeachment proceedings against Donald Trump and a diplomatic rift with the Europeans for Ukraine, was prompted by a complaint from a whistleblower who claimed that Trump might have abused power as he urged Zelensky to investigate the business dealings of Hunter Biden, former Vice President Joe Biden's son, with a Ukrainian gas company during a call this July.
After the report emerged, House Democrats launched an impeachment inquiry against the US president, claiming that he had committed “high crimes and misdemeanours”. However, Republicans have rejected the allegations, stressing that Trump has not violated any law, adding that the case is an operation ahead of the 2020 election.
Trump, in his turn, has also denied the allegations calling them another attempt at a political witch hunt to reverse the outcome of the 2016 presidential election, and published the transcript of the telephone call with Zelensky.
