Complex sentence: Kohl admitted that rarely had German-American relations been so strained, and in the days leading up to the visit, the White House and the Chancellery were pitted against each other in the blame game.
Split into simpler sentences: Kohl admitted that rarely had German-American relations been so strained. Indeed, it seemed that in the days leading up to the presidential visit, the White House and the Chancellery were pitted one against the other in the blame game.