Baja assumes his new post as the countrys permanent representative to the UN.
Sources said the government hopes to enlist the support of Washington in the Philippines bid for a seat in the UN Security Council. Manila has been a staunch ally of Washington in the war on terror and had supported the US-led war in Iraq.
The council has five permanent members: the US, Britain, China, France and Russia. There are 10 non-permanent members elected to two-year terms by the General Assembly. Currently these are Angola, Bulgaria, Cameroon, Chile, Germany, Guinea, Mexico, Pakistan, Spain and Syria.
Each council member has one vote. Decisions on substantive matters require nine council votes, including the concurring votes of all five permanent members.
Several non-permanent members supported the war in Iraq. But France, Germany and Russia openly opposed the war, fraying transatlantic alliances.
A threat by France to veto a second UN vote on a resolution that could have given an international green light for the war prompted Washington to forgo the vote.
Invoking an earlier UN resolution, the US-led coalition then pushed ahead with the war.
Baja, 66, is a former foreign affairs undersecretary for policy. He brings with him 41 years of diplomatic experience when he takes over the post vacated by former Ambassador Alfonso Yuchengco, who resigned in December.
Upon his arrival in New York, Baja is expected to oversee the efforts of the Philippine Mission to the UN to solidify the countrys bid for a non-permanent seat in the 15-member Security Council in November.
The Philippines became a non-permanent member of the Security Council in 1976, during the tenure of then Foreign Affairs Secretary Carlos Romulo, where Baja served as special assistant.
Baja leaves Manila a week after President Arroyo conferred upon him the Order of Sikatuna with the rank of Datu, the highest award for Filipino diplomats. He was cited for his outstanding accomplishments in international relations and foreign policy formulation.
In a press statement, the Department of Foreign Affairs (DFA) said Baja "has been credited for drafting and negotiating the 2002 Declaration of the Conduct of Parties in the South China Sea, as well as the Joint Statement on East Asia Cooperation for the 21st Century, which defined the (countrys) current stable and harmonious relations with China."
A law graduate of the University of the Philippines, Baja began his career in the foreign service as a legal officer for the DFA in 1962. He was Philippine ambassador to Italy before he was designated DFA undersecretary for policy in 1998.