The withering criticism that liberal Democrats are directing at Obama over a public insurance option as part of health-care reform shows his vulnerability. Similarly, his economic spokesmen created confusion about his (and their) resolve this month when they seemed to edge toward, and then back away from, tax increases on the middle class…

Obama has also left some Arab leaders with whom he recently met confused and doubtful about his intentions on Middle East peace. They have reported to aides that the president acknowledged that he has failed thus far to secure matching concessions from Arab countries and Israel as the basis for new negotiations…

If you want to see this president succeed, as I do, you can construct an alternative narrative in which he is throwing dust in the eyes of opponents and resolutely moving toward goals that are worthy, if not as exalted as those originally proclaimed.

But it hasn’t felt that way in this uneven August. In Washington the old saw about perception being reality is all too true. And all too final, once an impression of unsteadiness has been etched onto public opinion.