https://thespectator.com/topic/impeachment-inquiry-looms-joe-biden/
The signals coming from House Speaker Kevin McCarthy are that his Republican majority will soon launch a formal impeachment investigation. The final decision hasn’t been announced —
and an investigation is still a far cry from a full House vote. But setting up an impeachment committee is an essential first step. Most of his caucus wants to take it.
Most, but not all. The reservations of some Republicans and the calculations behind them are why McCarthy has moved slowly. The speaker’s problem is more than rounding up votes. The other problem is the investigation carries real risks as well as benefits.
The biggest benefit is a technical, legal one. It gives House investigators the power to compel testimony and documents from all Executive Branch agencies, even the most reluctant, as well as private parties. According to the Office of Legal Counsel, the Department of Justice’s in-house legal advisor, “The House of Representatives must expressly authorize a committee to conduct an impeachment investigation and to use compulsory process in that investigation” in order to compel testimony and document production. With that committee, they can go to court directly to demand compliance.
The president may be entitled to some protection for official communications, but, in 2020, the Supreme Court overwhelmingly rejected President Trump’s expansive claim that he and his aides had absolute immunity from congressional subpoenas. “Executive privilege” didn’t extend nearly that far. Instead, the High Court set standards to guide lower courts on what Congress could rightfully demand, including demands on the president himself.
The court’s standards are a multi-part test:
Subpoenas must be ‘detailed and substantial’;
They must have legislative purpose, which includes impeachment;
The materials must not be available to Congress another way; and
Compliance must not ‘unduly burden’ the president as he fulfills his other duties
The SCOTUS decision was “new law” since, for over two centuries, the president and Congress managed to resolve these disputes without the courts’ intervention. When that cooperation broke down, the court was forced to decide between the other two branches.