Germany and the IRA
Especially in the early months of the war the IRA had been the most important ally for the Germans. Abwehr II, the German intelligence agency under Erwin von Lahousen, had, against orders from the Foreign Ministry, taken up connections with the IRA after the beginning of its bombing campaign against Britain in January 1939. The Abwehr wanted to send agents to Ireland to strengthen relations with the IRA, many of whose leaders were, after de Valera's raids earlier in 1939, imprisoned. "The agents were to approach the IRA on the basis of Germany's desire to see Ireland united and persuade the organisation to abandon political activities in favour of military action."
Hempel was concerned about the effects the German intelligence activities in the country could have on diplomatic relations, but the Abwehr did not listen to him. He warned that the IRA was not strong enough for any action with a promise of success. After the raid on the Irish army magazine in Phoenix Park, Dublin, on 24 December 1939, the Dail decided to set up detention camps for the IRA. Shortly afterwards most of the leading circle of the IRA were imprisoned during a raid by the Special Branch. An attempt to strengthen the IRA again was the German plan to return the IRA leaders Sean Russell and Frank Ryan, who had been political opponents, to Ireland. At the time of the raid in January 1940, Russell had been on a campaign to raise money in the United States of America, and now he asked the Abwehr to help him return to Ireland, an appeal that delighted the German intelligence, providing it with yet another access to the IRA. The Abwehr managed to get Russell out of the USA and a plan was made for him to return to Ireland, called 'Operation Dove'. After his return on a U-boat the IRA leader would be given free hand in his actions, and he would figure out if joint activities with the Germans were possible. But the whole operation ended tragically, as Russell died on the voyage to Ireland, just in sight of his destination, without telling Ryan about his plans. Ryan therefore decided to return to Germany, where he eventually died in 1944