From Preservation Action:

This week the Biden Administration reached an agreement with the United Nation's Educational, Scientific, and Cultural Organization (UNESCO) for the United States to rejoin the organization in July. The U.S stopped paying their UNESCO membership dues in 2011 and withdrew from UNESCO in 2019 citing an anti-Israel bias. In December, lawmakers included provisions in the year end omnibus spending bill that the United States would pay back dues to UNESCO and cited specific plans to reengage with UNESCO.  Preservation Action joined a letter led by World Heritage USA urging support for this waiver.

Among many initiatives, UNESCO oversees the World Heritage Committee, which is responsible for implementing the World Heritage Convention and the inscription of sites to the World Heritage List. The US withdrawal from UNESCO and inability of the US to pay their annual dues, put future US World Heritage Site nominations in jeopardy. This includes the 2022 nomination of the Hopewell Ceremonial Earthworks in Ohio, which set to be considered by the World Heritage Committee this summer, and sites currently on the US Tentative List, such as the Moravian Bethlehem in Pennsylvania and Civil Rights Movement Sites. The decision of the U.S to rejoin UNESCO and pay it's back dues takes an important step in ensuring the US is once again in good standing and better positions future US nominations to the World Heritage List.