US President Donald Trump will be the second speaker to address the United Nations (UN) General Assembly when the high-level debates kick off Tuesday morning in New York, but he is gearing up to be the most-watched and most talked-about head of government in attendance.

Trump will be in the spotlight following a year of US policies that experts say have distanced America from the rest of the world and – in particular – the UN. 

"Relations between the Trump administration and the UN are pretty poor," said Richard Gowan, a senior fellow at the UN University's Center for Policy Research.

"We've seen Trump pulling back from a growing number of multilateral agreements, most notable the Iran Nuclear Deal, and also pulling out of the Human Rights Council," said Gowan. 

"So the US is disconnecting itself from the UN on many significant issues." 

Since Trump took office, the US has also reduced funding to the main UN budget and successfully campaigned to cut UN peacekeeping numbers. 

Washington has also exited the UN Educational, Scientific and Cultural Organization (UNESCO), withdrawn from the Paris Climate Deal and the Global Compact on Migration.

Most recently, the US stopped its funding for the UN's agency for Palestinian refugees, and against the wishes of a majority of nations recognized Jerusalem as the capital of Israel. 

The series of pullbacks by the US has roiled UN officials and worried diplomats. Without naming any country, the UN Chief last week warned about how multilateralism was under fire.

"Let me note one overriding concern in our increasingly globalized era," said UN Secretary-General Antonio Guterres to a roomful of reporters Thursday. "Multilateralism is under attack from many different directions precisely when we need it most." 

America has said it is putting "America first."

"We really value sovereignty of the country, we think every country should as well, regardless of who the country is," US Ambassador to the UN Nikki Haley told reporters at a press conference the same Thursday. 

"And so that's a conversation we want to have. It's not saying multilateralism can't work, but it's saying sovereignty is a priority over all of that," she added.

The UN and many countries may disagree with these US decisions, but the Trump administration's defense of America's interests and its criticism of the UN are not entirely unfounded. 

Other experts have long bemoaned excesses and abuses within UN agencies and called for reforms, but wonder if the Trump administration may have gone too far. 

Richard Gowan at UN University's Center for Policy Research said the changes may come with a cost down the road to the UN and the people it serves.

"I think that the UN is holding together reasonably well and you actually see European powers and countries like China stepping up to fill some of the leadership void that the US is creating," said Gowan. 

"But if the US continues to cut its funding to the UN, if the US undermines the political credibility of the UN on big issues like peace in the Middle East, then the organization will struggle. 

The fear is that a retreating US and a struggling UN could cause irreparable damage especially on the ground where its work is needed most… in places already volatile and vulnerable.

(Cover: US President Donald Trump addresses the 72nd Annual UN General Assembly in New York, US, Sept. 19, 2017. /VCG Photo)