WASHINGTON (NYTIMES) - After a rocket attack on the United States Embassy in Baghdad late last year, the Trump administration renewed its threats of withdrawing diplomats from Iraq. A military retaliation against Iran was discussed, and the White House warned of a drastic response "if one American is killed". None was.
Nor were any Americans killed in a similar strike on a US military base at the airport in Irbil, in northern Iraq, on Feb 15, which officials blame on an Iranian-backed militia.
One foreign contractor died, and a US service member and several contractors were wounded, prompting Secretary of State Antony Blinken to describe the US as outraged and another official to sternly promise "consequences for any group responsible".
But the Biden administration's otherwise measured response to the rocket fusillade stood in sharp contrast with former president Donald Trump's pitched campaign against Iran - one that often caught Iraq in the crossfire.
And it raised a question both in Washington and in Baghdad: What are President Joe Biden's red lines when it comes to responding to attacks from Iranian-backed militias that target Americans in Iraq?
Diplomatic and military officials said Mr Biden's larger goal was to lower hostilities between the US and Iran and its proxies in the region, including in Iraq, and to look for a path back to diplomacy with Iran.
This past week, the US extended an opening to new negotiations with Iran to limit its nuclear programme.
The effort for rapprochement comes as the Biden administration simultaneously stares down deadly militias in Iraq that officials believe are acting with Iran's help and, perhaps, orders. Attacks against Americans by Iran or its proxies could scuttle the broader diplomatic goal, the officials said.
They also could upend a fresh attempt by the US to persuade Iraq to lean away from Iran - without expecting to sever their spiritual, economic and cultural ties - by offering incentives instead of threats.
"In order for America to pursue our values and to pursue our interests around the world, we have to be engaged in the world," Mr Ned Price, the State Department's spokesman, said after the Irbil attack. "And, of course, engagement in some corners of the world carries added risks."
So far, two senior Defence Department officials said, there has been no detailed discussion at the Pentagon's Central Command about a specific military response to the strike in Irbil as US and Iraqi authorities investigate who launched the attack.
Both Mr Blinken and Defence Secretary Lloyd Austin, who served three combat tours in Iraq, have spoken with their Iraqi counterparts to offer assistance with the inquiry.
Officials blame the Irbil rockets on Iranian-backed militias, such as Kataib Hizbollah and Asa'ib Ahl al-Haq, which had been held responsible for similar previous strikes. But representatives at the White House, State Department and Pentagon have stopped short of making any specific accusations.
"What an important test for the new administration," Ms Simone Ledeen, Pentagon's top Middle East policy official until last month, said on Twitter on Feb 15. "Will be interested to see if there is a response."
Iraqis have long been suspicious of US officials who, after ordering a military invasion in 2003 and deposing Saddam Hussein, are still blamed for the security vacuum that followed after US occupation authorities disbanded the Iraqi army.
Anger towards the US flared again last month when the Trump administration pardoned four American security contractors for their roles in a 2007 massacre of 17 Iraqi civilians in Nisour Square in Baghdad.
Mr Blinken has begun what one senior State Department official described as a review of US policy in Iraq that allows for a shift in approach. The review will include feedback from the Pentagon before it is presented to the White House, possibly as soon as next month.
The administration is considering returning hundreds of diplomats, security personnel and contractors to the embassy in Baghdad; the numbers were reduced in May 2019 during a period of heightened tensions with Iran, touching off fluctuating staffing levels ever since.
The State Department is not yet ready to reopen its consulate in the southern Iraqi city of Basra, a key listening post near Iran's border that the Trump administration closed in September 2018 after the airport compound where it was based was rocketed by militias. Nobody was injured in that attack.
The department is also looking at extending limits that the Trump administration imposed on how much energy Iraq's government can buy from Iran - an arrangement that critics warn could fund Iran's aggressions but provides a lifeline for millions of people who would otherwise go without electricity.
Iraqi banking officials met this past week with US diplomats over the issue, which currently forces Baghdad to ask Washington every few months for a waiver to buy energy without facing sanctions.
Two other Biden administration officials said the US Agency for International Development also is weighing sending more humanitarian aid to parts of Iraq, mostly in the country's western and northern regions, that were hit hardest by the Islamic State in Iraq and Syria militant group.
But several Pentagon officials and senior military officers said it was unclear what the Biden team's red lines were when it came to protecting US personnel in Iraq from Iran or its proxy fighters.
After a rocket attack that killed an American contractor in December 2019, the US blamed Kataib Hizbollah and bombed five of its bases. That led to a siege at the US Embassy, where protesters trapped diplomats inside the sprawling compound for two days and, in turn, prompted Mr Trump to order a military strike that killed Iran's most revered general while he was visiting Baghdad.