Washington: Barack Obama is gaining steadily on Hillary Clinton among Democratic superdelegates, nearly erasing her last advantage in a presidential race where those party insiders could be the ultimate kingmakers.

In a danger sign for Clinton, Obama over the past few months has sharply cut her lead among superdelegates - nearly 800 elected officials and party leaders free to back any candidate.

Neither Obama nor Clinton is likely to win enough pledged delegates in state contests to clinch the hard-fought battle for the Democratic presidential nomination, leaving superdelegates to decide the race. The Democratic nominee will face Republican John McCain in the November election.

Meanwhile, McCain has erased Obama's 10-point advantage in a head-to-head presidential matchup, leaving him essentially tied with both Democratic candidates, according to a new poll.