On August 14, 2008, in Tripoli, Welch signed the U.S.-Libya Comprehensive Claims Settlement Agreement paving the way for the restoration of full diplomatic and commercial relations between the two countries after a 25-year break.

From 1989 to 1991, he was a member of the National Security Council staff at the White House and became executive assistant to the Under Secretary for Political Affairs at the State Department (1991-2).

Between 1996 and 1998, Welch served in the State Department's Bureau of Near Eastern Affairs, playing an important role in achieving U.S. foreign policy objectives in Iran, Iraq and Libya.

He has also criticized a Friday sermon by the Grand Imam of al-Azhar, Muhammad Sayyid Tantawy, that described the Jews as the "descendants of monkeys and pigs."

[13] According to Al Jazeera, papers found in the headquarters of the former intelligence agency of Libya indicate that during the 2011 Libyan civil war Welch met officials of Muammar Gaddafi's regime on August 2, 2011, at the Four Seasons Hotel in Cairo a few blocks from the US embassy.

[14] Welch reputedly advised the Gaddafi regime on how to win the "propaganda war" by passing information on potential connections between anti-Gaddafi forces and terrorist organisations such as Al Qaeda to the American government via the intelligence agencies of other countries such as Israel, Egypt, Jordan, and Morocco.

[14] According to it he also recommended that the regime refers to the Syrian situation to expose what he viewed as a double standard in American foreign policy relating to the Arab Spring.

Speaking at a Congressional hearing for the House of Representatives in 2007, Welch articulated that the Department of State sided with Morocco on the issue of Western Sahara.

He explained that the conflict is a, "…destabilizing element [which] thwarts regional ties, which are necessary for economic expansion, and it has had an effect on government-to-government cooperation within the Maghreb.