Yes, politics, the press and the strenuous rigors of the campaign trail is hard enough for much younger and healthier campaigner's.
I worry about his health too, but I honestly can't think of anyone better suited, or capable of fulfilling the critical and expanded role of mentor and adviser, as well as V.P., that Cheney provides the President.
Was on the Cheney bandwagon before he agreed to serve and everytime I hear him speak in person I am reminded how much I admire this man and his great wisdom and vision. I wanted him to run for Pres in 1996! Personally I hope he stays on the ticket -- no one better IMHO.