Acting on a mix of principle and caution, Justice Department officials under former President Joe Biden made a series of decisions that significantly delayed and ultimately may have hampered the federal criminal investigations into President Donald Trump, according to a new book.

The slow decision-making at the top of Attorney General Merrick Garland’s Justice Department affected two major probes into Trump after he lost the White House in 2020: whether he illegally possessed and obstructed the retrieval of classified documents at his Mar-a-Lago residence, and whether he conspired illegally to overturn the 2020 election.