A lot has happened in papal politics since Henry IV, the Holy Roman Emperor, stood barefoot and hatless at the gates of Canossa castle begging pardon from Pope Gregory VII. That was 932 years ago while popes were slugging it out with temporal rulers like Henry over who had the right to appoint bishops.
As current practice shows, the popes won that protracted battle but eventually lost the war over the control of worldly affairs. Though the popes can exert moral influence, they lost the ability to direct international affairs a long time ago (“how many divisions does the pope have,” Stalin famously quipped).
Benedict XVI, therefore, lacks anything like the clout of Gregory VII. Unable to dish out many favors, however, he might seek a big one from Barak Obama when the President comes calling in July. Obama could be seen as good medicine for a struggling papacy: a popular, gregarious young politician who has won widespread admiration and popularity, some of the very things Benedict needs to prop up a sagging reign.