WASHINGTON — One weekend last month, American forces drove into the Marja area of southern Afghanistan, opening the biggest military operation of the Obama presidency. In the five weeks since then, President Obama has made 38 speeches, statements or other public remarks and never once mentioned the operation.

In recent public appearances, like this one on Friday in Fairfax, Va., President Obama has focused his remarks largely on the campaign for a health care overhaul.

In fact, amid roughly 100,000 words uttered in these mostly scripted events during that period, the terms “Taliban,” “Marja” and “terrorist” have never passed his lips. Nor has he had anything to say about settlement construction in East Jerusalem,...