First, he said he was pulling US forces immediately, then there were delays and now nearly 20 per cent of the troops will stay indefinitely.
In the latest change to America’s situation in Syria, US President Donald Trump has authorised hundreds of troops to remain.
The decision to remove America’s presence sparked concern among key allies, who were worried it would lead to more instability that could allow ISIS to regain ground.
Although the US administration claimed it was a “tactical” shift in the war against the terror group, not a strategic one, analysts have warned that the Pentagon would find it more difficult to co-ordinate allies and lead the international coalition against ISIS without being in Syria.
Mr Trump agreed to allow about 200 US soldiers to stay in Syria’s north-east indefinitely.
The news will be well received by the US-backed Syrian Democratic Forces, who have worried that the American withdrawal would embolden Turkey to launch an assault on them.
The presence of US forces has been a key stabiliser as Washington has warned its Nato ally that any assault on the SDF would endanger American troops.
Mr Trump has also approved the Pentagon’s plan to keep a further 200 soldiers at Al Tanf garrison in Syria’s south to train local forces to help root out the remains of ISIS in the country.
The president’s decision endorses a plan, pressed by US military leaders for some time, calling for an international force of 800 to 1,500 troops that would monitor a safe zone along Syria's border with Turkey.
Mr Trump in December announced he was pulling all 2,000 US troops from Syria imminently, but he has gradually reversed course.
The move also sparked a fiery response from Senator Jack Reed, who called the decision a "betrayal of our Kurdish partners".
"The whole system is screaming in agony against the US president's order," Michael Knights, a senior fellow at the Washington Institute for Near East Policy, previously told The National.
“I think fair to say every person in the US administration knows the situation bar one.
"Everyone is lined up behind a continuing mission and the challenge isn’t that the White House doesn’t understand what’s at stake, the issue is that they’re trying to fulfil the president’s order while ameliorating the situation.”
US officials told AP that Mr Trump made the decision to keep some forces on in Syria after being told by European allies that America had to contribute to the observer force or they would not take part.
The Washington Post reported last week that European Nato allies had unanimously told the US that they would not stay in Syria if America left.
Although the official didn’t say which country, only the UK and France have troops there.
Gen Joseph Dunford, chairman of the Joint Chiefs of Staff, has been leading discussions with allies on the observer mission.
Gen Dunford said on Friday that he was confident they would commit troops.
"I'm confident we can maintain the campaign," he said.
Acting Defence Secretary Patrick Shanahan described the move to keep 400 US troops in Syria as “good progress”. He then met Turkish Defence Minister Hulusi Akar at the Pentagon.
Officials said the US troops would remain in the area indefinitely to keep their Kurdish allies and Turkish forces from clashing, stop forces loyal to Syrian President Bashar Assad from seizing the territory and minimise the risk of an ISIS resurgence.
A defence official said Turkish and Syrian opposition forces would not be allowed in the safe zone.
The SDF is involved in a stand-off over the final sliver of land held by ISIS in eastern Syria, close to the Iraq border.
The US is not seeking a UN mandate for the observer mission and does not envision asking Nato to sponsor it, an administration official said.
He added that the troops would not be peacekeepers, a term that carries restricted rules of engagement.