Last week, within days of the world's leading producers agreeing to cut output in response to the coronavirus pandemic, a top lobbyist at Hogan Lovells sent out a barrage of emails on behalf of one of the firm's longtime clients: Saudi Arabia.

"We wanted to update you on how the Kingdom of Saudi Arabia (KSA) is leading global efforts to stabilize oil markets," wrote Norm Coleman, a Hogan Lovells senior counsel and former U.S. senator, in a message sent to more than two dozen congressional aides.

"The coronavirus pandemic has dramatically lowered global energy demand, harming producers around the world. As it has done for decades, KSA assumed its role as a global energy leader to negotiate this deal and help reduce the market imbalance," he added.