"The trend lines [for Abadi] are not good," said Doug Ollivant, a former military planner in Baghdad and senior fellow at the New America Foundation. "He needs a win - and preferably a string of two or three."
Obama's announcement yesterday will put US service members inside the Iraqi headquarters overseeing the offensive to recapture territory lost last month to Isis in Ramadi and surrounding Anbar province.
In a reflection of the President's conviction US military power cannot win the war, the plan will not allow US advisers to move closer to the frontlines where their support could boost the morale of Iraqi troops fighting to retake the strategically important city of Ramadi, west of Baghdad.
Neither does the new deployment include forward air controllers, who could direct air strikes from US bombers. It also does not envision the use of Apache attack helicopters, among the most lethal weapons in the US arsenal in urban combat.
Taken together, the steps and limits show Obama's deep-seated conviction that only the Iraqis can resolve a fight driven by Sunni feelings of anger, persecution and abandonment at the hands of the Shia Government in Baghdad. His focus, for now, is on forcing the Iraqis to solve their own problems. He is also determined to keep Americans - who have not suffered a single combat casualty in the fight against Isis in Iraq and Syria - out of harm's way.
"The loss of Ramadi needed a response," said Brian Katulis, a senior Middle East analyst at the left-leaning Centre for American Progress. "I see this as more of a tactical shift. The focus is still on getting the Iraqis to pull their own weight. It is important, but largely tactical."
Senior White House officials yesterday emphasised the immediate benefits hundreds of new advisers would bring to the fight against Isis.
The US troops inside the Iraqi headquarters will provide intelligence about enemy movements, ensure Baghdad responds to shortages of weapons, fuel and food in the field and help commanders ensure air strikes happen more quickly.
The White House also hopes the extra US help will steady Iraqi commanders who have ordered retreats even when their forces have vastly outnumbered their Isis enemies.
"When we're fused with them and advising and assisting, we're able to kind of see a little better - and buck up the ranks," said Brett McGurk, a deputy assistant secretary of state overseeing Iraqi policy. "I think this will have a fairly dramatic effect ...
"Sometimes the enemy [are] not as strong as they pretend to be."
In the attack on Ramadi, Isis fighters sowed panic by setting off suicide truck bombs and ambushing Iraqi troops from multiple directions. Even though the Iraqis outnumbered their attackers in some areas by as many as 40 to one, they still fled, said senior military officials. Their collapse has provoked widespread frustration in the Pentagon, where US military officials complain of repeated Iraqi leadership failures, poor discipline and ineffective systems for keeping the military running.
The problem, say these military officials, is not that Isis fighters are especially good, but that Iraqi Army forces are so bad.
"There is a sense that the whole thing will just take more time," said a senior US official who noted the Administration was only eight months into a three-year plan for Iraq and Isis faced its own problems.
American attack planes had killed thousands of the group's fighters, US officials said. To hold on to power in its areas, Isis relied on brutal repression and had struggled in recent weeks even to feed its own people.
US officials hope that as the months pass, Sunnis, who have passively supported Isis, will turn on the group. A major focus for the new trainers headed to Iraqi will be forging ties with Sunni tribes.
"It's critically important to get the Sunnis in the main security forces," said Elissa Slotkin, assistant secretary of defence for international security affairs. "That's another reason we want US forces on the ground to help facilitate that conversation."
More than a dozen years of war have made that conversation increasingly difficult. Iraq's Sunni population today is deeply fractured, demoralised and in some cases willing to embrace Isis over the Shia-led Government. While many Sunnis were happy to see the Shia Nouri al-Maliki step down as Primer Minister last year, they are already growing disillusioned with Abadi.
Republicans, meanwhile, have seized on the holes in Obama's plan, saying it will not do enough to heal Iraq's sectarian fissures. "Disconnected from a broader coherent strategy, it is not likely to be any more successful than our previous efforts," said Texas Representative Mac Thornberry, chairman of the House armed services committee.
Healing those sectarian wounds could take years. This week, Obama praised Abadi for his commitment to a "political agenda of inclusion", even as he acknowledged that his outreach to disaffected Sunnis only weakened his position with his Shia base.
"He's inheriting a legacy of a lot of mistrust," Obama said. "He's having to take a lot of political risks."
The US troops are due to arrive at Iraq's Taqaddum air base outside Ramadi in the next few days. It was not clear how long they will stay.
Obama's modest troop boost amounted to an acknowledgment the US is still in for a long war.
Meanwhile, US military officials will rely on targeted counter-terrorism raids by Special Operations forces and air strikes to minimise the threat to the US.
