http://www.bbc.com/news/world-asia-37147630

This might just be politics, but how would world heritage sites in the Philippines be impacted if the Philippines did withdraw from the UN?

On a side note, if I recall correctly the US left UNESCO under Reagan and joined again under Bush 43 and was still able to keep and nominate sites, would a similar scenario occur if the Philippines left the UN?

As the US (and I believe the UK followed suit) only left UNESCO and again (US only) is not paying dues but still getting WHS, perhaps that's why the sites remained. But obviously neither country acquired any new sites during this "dark age." My guess is that the Philippines would retain their World Heritage Sites but I think leaving the UN as a whole is of a different magnitude.

You can be a signatory to the World Heritage Convention without being a member of the UN.

The Vatican and Palestine are not members of the UN, nor are the Cook Islands. Also, Switzerland only joined the UN in 2002, yet it signed the convention in 1975 and had it's first world heritage site in 1983.

Good point. I wonder if the Philippines would be revoking their membership of the WHC. I would suspect they keep their current sites, also. I think it will depend on the rest of this possible change that determines acquiring new sites.

Can a country be a signatory to the WHC but not be a member of UNESCO?

Article 32 of the WHC

1. This Convention shall be open to accession by all States not members of the United Nations Educational, Scientific and Cultural Organization which are invited by the General Conference of the Organization to accede to it.
2. Accession shall be effected by the deposit of an instrument of accession with the Director-General of the United Nations Educational, Scientific and Cultural Organization

I doubt they would withdraw from the WHC as it has nothing to do with the current controversy, and it helps bring in tourism money.