Annen is an advocate of continued German commitment in Afghanistan and has visited the country on multiple occasions during both of his terms in the Bundestag. Amid discussions in the Social Democratic Party on whether to terminate Germany's mandate for German elite commando troops within the US-run Operation Enduring Freedom (OEF) against Taliban fighters, Annen in 2007 said many SPD members were questioning Germany's continued role in the anti-terror battle in Afghanistan. He stated that "say [the SPD is losing its way as a party oriented to finding peaceful solutions to international problems". Along with Green MP Jürgen Trittin, Annen claimed that the American counterinsurgency mission was hindering civilian reconstruction under the umbrella of the second mission, the International Security Assistance Force, because of what they called a heavy-handed approach by the U.S. military on the ground that was alienating the local population. In 2014, he voted in favor of continuing German participation in ISAF.