Obama moves closer to key cabinet pick

By Caren Bohan and Jeff Mason

CHICAGO (Reuters) - President-elect Barack Obama moved closer to filling a key spot in his cabinet on Tuesday as his transition team plotted a careful course to shaping the next U.S. administration.

A Democratic source said a conditional offer for the post of attorney general had been made to former Clinton administration official Eric Holder, making him the automatic front-runner for the nation's top law enforcement position.

Secretary of Defense Robert Gates had also been approached about staying in his position, the senior Democrat said.

In keeping with his decision to maintain a low profile during the transition period before he takes office on January 20, Obama spent most of the day in private meetings at a federal office building near his home in Chicago.

But he delivered a video address to a global warming conference and pledged to "engage vigorously" in international climate change talks when he becomes president.

The Democratic president-elect, who will succeed Republican President George W. Bush, told the conference in California he would stick to his promise of a sharp reduction in U.S. greenhouse gases by 2020 despite the ongoing financial crisis.

While Holder emerged as the top candidate for attorney general, Obama also continued to weigh the idea of naming his former rival, Hillary Clinton, as secretary of state.