He DIDNT cause war
Bethmann Hollweg did try to stop the Kaiser, urging him to be cautious in the run up to war, however it was too little too late
He was not in the same room, when they came up with the Blank Cheque, so can be suggested therefore that he wasn't responsible. Bethmann Hollweg perhaps only supported the Kaiser because if he didn't it would be likely he would lose his job - especially after the failure of Army Bill 1913.
He caused war, and weaknesses
He was hardworking but inexperienced. He had little knowledge of Foreign Policy - allowing the Kaiser to easily exploit this…