Democratic Sen. Barack Obama continues to lead Republican Sen. John McCain in the presidential race among likely voters in Pennsylvania, according to the latest Quinnipiac University poll released this morning.

Mr. Obama holds a 49-42 percent lead over Mr. McCain in the state, the same margin the Illinois senator held in the poll last month.

Mr. Obama is the favorite among independent voters, white women and blacks, and Mr. McCain leads among white men, blue-collar workers and Catholics. The poll was conducted before Mr. Obama announced the selection of Delaware Sen. Joe Biden, a Catholic and Pennsylvania native, as his running mate.

Quinnipiac University polls are conducted simultaneously in Florida, Ohio and Pennsylvania, three so-called swing states.

"While Obama leads easily in Pennsylvania, he ties McCain in Ohio, and the Arizona senator leads by four points in Florida," said Clay F. Richards, assistant director of the Quinnipiac University Polling Institute. "No president since 1960 has been elected without carrying two of the three key states."