ON THE CAMPAIGN TRAIL (AP)  -- Barack Obama has erased Hillary Rodham Clinton's once-imposing lead among superdelegates, after adding more endorsements this weekend from the group of Democrats who will decide the party's nomination for president.

Obama added superdelegates from Utah, Ohio and Arizona, as well as two from the Virgin Islands who had previously backed Clinton. The additions enabled Obama to surpass Clinton's total for the first time in the campaign. He had picked up nine other endorsements on Friday.

The milestone is important because Clinton would need to win over the superdelegates by a wide margin to claim the nomination. They are a group that Clinton owned before the first caucus, when she was able to cash in on the popularity of the Clinton brand among the party faithful.

Those party insiders, however, have been steadily streaming to Obama since he started posting wins in early voting states.

Superdelegates are the party and elected officials who will automatically attend the Democratic national convention this August in Denver. They can support whomever they choose, regardless of what happens in the primaries.

They are key, because neither Obama nor Clinton can win the nomination without them.

Clinton was spending Mother's Day on the campaign trail in West Virginia, after raising money for her cash-strapped presidential effort yesterday in Manhattan.

Rival Barack Obama and Republican John McCain were both taking the day off.

But Obama has already begun sketching the outlines of a general election campaign against McCain.

The Democratic frontruner is also planning stops in states where the primaries are over, including a trip Tuesday to Missouri. Later, he'll visit Michigan and Florida, two battleground states whose Democratic primaries were essentially nullified when state leaders defied the national party and cut in line.

McCain, meantime, has lost the man he had picked to run the Republican National Convention. Doug Goodyear quit yesterday over a report his lobbying firm once represented Myanmar. Goodyear says he didn't want to be a distraction.