• He has conveyed that important decisions are open for public pressure and bargaining.

The most vivid example is the ongoing debate over who Obama should select to replace Ben Bernanke as chairman of the Federal Reserve. Unlike in Syria, in which the timing of difficult decisions is largely outside Obama’s control, this involves a decision that has been on Obama’s calendar for months. Yet Obama allowed an internal debate to become an external one — inviting his own fellow Democrats to choose up sides in a kind of shirts-versus-skins competition between backers of Larry Summers (a favorite of many West Wing insiders) and Janet Yellen (a favorite of many liberals who believe Summers is temperamentally ill-suited and too close to Wall Street.)

• He has diluted the power of his own words.

Most recently, the attention has been on Syria. Obama declared two years ago that Assad must leave power, a goal that turned out to be impervious to U.S. policy. A year ago, he declared that use or movement of chemical weapons was “a red line” — an improvised phrase, aides said — and even now it remains unclear how severe the penalty will be for the regime’s deadly nerve-gas attacks last month against Syrians.