[6] During his time in office, German military forces were engaged in numerous UN-linked operations outside the NATO region, including 1,700 soldiers in Somalia (logistic support); 122 in Cambodia (medical unit); two ships with combined crews totaling 420 people in the Adriatic Sea (air-navy patrol); 60 in Bosnia-Herzegovina (relief flights), and 40 in Iraq (UN monitoring staff).

[9] Under Rühe's leadership, Germany began destroying stockpiles of tanks and other heavy weapons in August 1992, becoming the first country to implement the Treaty on Conventional Armed Forces in Europe.

[12] In 1997, Rühe suspended a lieutenant general and instituted disciplinary action against a colonel after it was revealed that Manfred Roeder, a neo-Nazi with a criminal record of bombings, had been invited to give a speech to the country's most prestigious military academy in 1995.

[24] In 2000, as part of the search for a new chair of the CDU, Rühe led an effort to stop frontrunner Angela Merkel that included overtures to Kurt Biedenkopf to serve as an interim leader.

[26][27] In 1985, Rühe strongly urged that Europe's four major powers – France, Britain, Italy and West Germany – formulate a common European position on the Reagan Administration's Strategic Defense Initiative.

He was quoted by Neue Presse expressing sympathy for Putin and arguing for an intensive dialogue between the German government and "the Kremlin" on the subject of the American proposed "missile defense system".

In 2015, he joined other foreign policy experts, including Igor Ivanov and Ana Palacio, in calling for a possible Memorandum of Understanding between NATO and the Russian Federation on the Rules of Behaviour for the Safety of Air and Maritime Encounters between the two sides.