BERLIN — In the early 19th century, the German military theorist Carl von Clausewitz concluded that war is an act of politics pursued by other means. Two centuries on, a student of modern conflict might be forced to recast the doctrine for the globalized, 24-hour-news-cycle era: War is a political act pursued to the extent that politics itself permits.

In recent days, indeed, as Western leaders wrestled with claims of chemical weapons use on the outskirts of Damascus on Aug. 21, the balance between politics at home and the ability to project military power abroad seems to have shifted into a new and more circumspect era, as voters tire of fruitless wars overseas and of their leaders’ rationales for fighting them.

When the contenders for the German leadership in elections this month faced off in a televised debate the other day, for instance, the gathering showdown over Syria seemed almost a postscript.

Only when the 90-minute discussion between Chancellor Angela Merkel and her Social Democratic challenger, Peer Steinbrück, was in its final stages did it turn to the question of whether Germany should participate alongside the United States in any military intervention in Syria.