"Over the course of my three terms in the Senate and five terms in the House, I have accumulated seniority and important committee assignments that are valuable to Idaho, not the least of which are my seats on the Appropriations Committee, the Energy and Natural Resources Committee and the Veterans' Affairs Committee. A replacement would be highly unlikely to obtain these posts.
Mitch McConnell needs to publicly promise that if Craig resigns, his replacement will be given seniority and committee assignments identical to Craig's. And, if that person is elected in their own right, he or she will continue to have Craig's seniority and committee assignments. This is a better deal for the people of Idaho than if Craig serves out his term and a brand new Senator is elected without any seniority.
Craig would then be "sacrificing himself" for the benefit of the people of Idaho, whom he obviously is so dedicated to serving.