By Dale McFeatters
Scripps Howard News Service

President Barack Obama's plan to do a one-day drop-by at the U.N. climate-change summit in Copenhagen has the makings of a public-relations gaffe.

He will arrive early in the conference and depart for Oslo to pick up his Nobel Prize, but, as of now, there are no plans for him to return for the remainder of the conference. Most of the 65 to 75 world leaders expected to attend will stay for the full 11 days, particularly the important closing sessions.

A delegation of Cabinet officers and senior White House aides will stay for the duration of the conference, but that is unlikely to make up for the absence of Obama and the celebrity and publicity he would bring.

Still, Danish Prime Minister Lars Loekke Rasmussen, who is presiding over the talks, said, "The visit underlines the president's desire to contribute to an ambitious, global agreement in Copenhagen."

But he is not coming armed with what climate-change activists want most: Mandatory reductions in U.S. greenhouse-gas emissions. Instead, he will endorse the reductions in the House-passed greenhouse-gas bill ― a 17 percent reduction from 2005 levels by 2020.

Passage of that bill or a slightly stronger Senate measure is by no means assured because of deep congressional reservations over the economic cost of mandatory reductions. And still to come is the political fallout of hacked e-mails that seem to show leading climate-change scientists playing fast and loose with data.

Obama will trumpet other steps he has taken ― the $80 billion the United States is spending on clean energy and tougher auto-mileage standards by 2016. But the other leaders are likely to be dissatisfied by anything less than mandatory U.S. reductions in heat-trapping gases.

Dale McFeatters is a Scripps Howard columnist.