ABC newsman George Stephanopoulos, who once played a key role in Bill Clinton's presidential campaign, and then in the Clinton White House, said Wednesday that, "More superdelegates will come out today for Barack Obama. They will come three, four, five at a time, and this nomination will be locked up."

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On Wednesday, at least four superdelegates did just that. Jeanette Council, an undecided superdelegate from North Carolina, said she decided over the weekend to endorse Sen. Obama but waited until after voters cast their ballots to announce it on Wednesday. The Obama campaign announced three other supporters: North Carolina Democratic Party Chairman Jerry Meek, North Carolina Democratic National Committee member Jeanette Council and California DNC member Inola Henry.

Earlier in the day, former senator and presidential candidate George McGovern urged Clinton to drop out of the race. He endorsed Sen. Hillary Rodham Clinton before the Iowa primary, but on Wednesday he endorsed Obama.

After watching the returns from the North Carolina and Indiana primaries Tuesday night, McGovern said Wednesday it's virtually impossible for Clinton to win the nomination. The 1972 Democratic presidential nominee said he had a call in to Bill Clinton to tell him of the decision, adding that he remains close friends with the Clintons.

"I will hold them in affection and admiration all of my days," he said of the Clintons.

McGovern's announcement comes a day before Clinton was scheduled to travel to South Dakota to campaign. The state holds its primary June 3 with 15 pledged delegates at stake.

McGovern said he had no regrets about endorsing Hillary Clinton months ago, before the Iowa caucuses.

"She has run a valiant campaign. And she will remain an influential voice in the American future," he said.

But Obama has won the nomination "by any practical test" and is very close to a majority of the pledged delegates, said McGovern, who is 85. Obama moved within 200 delegates of clinching the nomination with his split decision on Tuesday of a win in North Carolina and a narrow loss in Indiana.

It's time to unite the Democratic Party, he said.

"Hillary, of course, will make the decision as to if and when she ends her campaign. But I hope that she reaches that decision soon so that we can concentrate on a unified party capable of winning the White House next November," he said.

Clinton lent her presidential campaign $6.4 million over the past month, her campaign said Wednesday, underscoring the financial advantage held by her rival.

The money more than doubled Clinton's personal investment in her bid for the Democratic nomination. She gave her campaign $5 million earlier this year.

Obama's campaign on Wednesday weighed ways to bring the drawn-out Democratic nominating process to a close while mapping out a strategy that will involve campaigning in battleground states where primaries have already been held.

Republican nominee-in-waiting John McCain has "run free for some time now" because of Democratic preoccupation with the ongoing primary fight, said Obama strategist David Axelrod. "I don't think we're going to spend time solely in primary states," he said. "We have multiple tasks here."

The Illinois senator was enjoying a rare down day in his hometown before returning to Washington, D.C., late Wednesday.