President Barack Obama is away from Washington, rallying public support for his second-term agenda. But to state the obvious, there's an even more critical voting bloc he must win over: members of Congress.

Many of the president's more ambitious State of the Union proposals are already generating sparks among lawmakers back in the nation's capital and face an uncertain future -- and not just from Republicans.

One initiative he mentioned briefly in Tuesday night's address has potentially far-reaching economic consequences: the launching of free-trade negotiations between the United States and the European Union.

The U.S. and Europe already account for nearly half the world's economic output and such an alliance could bring benefits to both sides of the Atlantic as well as making it easier to compete with China, a rising economic powerhouse.

Generally free-trade agreements draw more support from open-market Republicans and business leaders. Democratic President Bill Clinton had to overcome fierce labor union and Democratic resistance to win approval of the North American Free Trade Agreement in 1993.

Obama was accused by Republicans during last year's campaign of being too European in his thinking. Also, Europe is still confronted by even more dire economic woes than the U.S.

The German economy, Europe's largest, shrank by a worse-than-expected 0.6 percent in last year's final three months, figures out Thursday showed.

So even if Obama is able to negotiate such a complicated deal, he's likely to face some union and Democratic grousing as well as reviving GOP accusations that he wants to make the U.S. more like Europe.

Still, "the stars could well be aligned" this time for such a deal, said Michael Froman, the top White House trade expert.

The president was in Decatur, Ga., on Thursday promoting his plan to expand preschool programs significantly. He plugged his minimum wage and manufacturing proposals Wednesday in North Carolina and will push his gun-control proposals in Chicago on Friday.