July 12, 2014 at 1:00 am

The worst president?

Wow. A reputable poll shows that the public believes Barack Obama is the worst president since World War II. Worse than Richard M. Nixon, driven from the presidency by Watergate? Much. Worse than Jimmy Carter, for decades the very symbol of the feckless chief executive? Loads. Worse than George W. Bush, still a lightning rod on the left and a symbol of disappointment on the right? Definitely.

These startling poll results set loose a flurry of told-you-so nods on the right and a fusillade of this-tells-us-nothing assertions on the left. Obama is in trouble, no matter how carefully you peel through the Quinnipiac University poll that is causing such a firestorm. Thereís almost no good news there, or anywhere else, for the president. Then again, this worst-president poll sheds little light. Almost every veteran observer of polls and presidents will likely attest to that.

First, the trouble. Obama has it, in several dimensions. The public is split evenly ó 48 percent to 48 percent ó on whether the president is honest and trustworthy. Itís split fairly evenly on whether he has strong leadership qualities, with a slight advantage to those who think he doesnít.

Hereís the big one. By a fairly substantial number (45 percent to 38 percent), the public believes the nation would be better off had former Gov. Mitt Romney of Massachusetts been elected two years ago.

Now, the sobering bucket of cold water for the Obama critics. With the exception of three occupants of the White House (all war presidents), presidents tend to grow in stature as their administrations grow more distant in the rearview mirror. The exceptions are three of the most beleaguered modern presidents: Lyndon B. Johnson (Vietnam), Nixon (Watergate) and George W. Bush (Iraq and Afghanistan).

Foreign crisis doesnít assure that phenomenon, however. Carter is rated substantially more favorably today than he was when he was in office, and he dealt with a hostage crisis in Iran that persisted for 444 days and, arguably, doomed his presidency. George H.W. Bush is also more favorably regarded today than he was while in office, and he was a war president (Desert Storm).

The canary of caution in this political coal mine is the poll rating for Harry Truman, who left office with a 32 percent approval rating ó and a 56 percent disapproval rating, according to Gallup.

In the Quinnipiac survey, zero percent of Americans singled out Truman as the worst of the last dozen presidents. That figure applies to Republicans as well as Democrats.

The message here is not that Obama isnít troubled as he rounds the clubhouse curve and heads toward his seventh year in office. It is that Americansí judgments arenít final.

David Shribman is executive editor of the Pittsburgh Post-Gazette.