WASHINGTON -- President Barack Obama outlined Tuesday the nation's first comprehensive effort to curb vehicle emissions while cutting dependence on imported oil, calling the plan an historic turning point toward a "clean-energy economy," according to The Associated Press.

Joined in the White House Rose Garden by leaders of the auto industry, labor, government officials and key national and state political leaders, Obama said the agreement that once would have been "considered impossible" was what he termed a "harbinger of a change in the way business is done in Washington."

The two-pronged approach to problems that compound threats to the global environment marks the latest in a series of shifts by the Obama administration away from the policies of his conservative predecessor, former President George W. Bush.