Federal authorities would have needed to meet an extraordinarily high threshold for probable cause to sign off on such a high-profile, politically explosive operation, legal experts say.

Bharara had a snickering response to news that his successor as top federal prosecutor was stepping down from the job. (AP Photo/Andrew Harnik, File)NEW YORK Former Manhattan U.S. Attorney Preet Bharara had a snickering response to news that his successor as top federal prosecutor was stepping down from the job. Doesn't sound like stepping down, Bharara tweeted soon after the announcement was made Friday night that Geoffrey S. Berman was out. He explained he was appointed by Manhattan federal judges and wouldn't budge until a successor was confirmed by Congress. A few months into his work, Manhattan judges appointed him permanently because Trump never formally nominated him.

Still, he was stunned by a Friday night phone call saying President Donald Trump had fired him. He demoted Glenn Fine as acting Defense Department watchdog, stripping him of oversight of the $2 trillion coronavirus relief effort. Democrats have raised questions about whether a Transportation Department acting inspector general who was removed was replaced for political reasons, too. All presidents take umbrage at inspector general oversight, a post-Watergate concept meant to root out waste, fraud and corruption. Chuck McCullough, the intelligence community inspector general under Obama, said he maintained a sparsely decorated office, aware he could be fired any time.