WASHINGTON -- Barack Obama begins his presidential race against John McCain with a lead in the latest Wall Street Journal/NBC News poll, but not so great an edge as might be expected, given the gale-force political headwinds against Sen. McCain's Republican Party.

Sen. Obama leads Sen. McCain by 47% to 41%, a spread that is twice the edge he had in the previous poll, in late April. Still, that lead is significantly smaller than the Democratic Party's 16-point advantage, 51% to 35%, when voters are asked, without candidates'...