Another first: billion-dollar presidential campaign

WASHINGTON (Reuters) - If Barack Obama looked like a campaign fund-raising champ before this week, just wait.

Now that he has captured the Democratic presidential nomination to face Republican John McCain in the November election, the Illinois senator will try to lay claim not only to many former Hillary Clinton donors, but also Democrats who have been undecided until now.

The result is likely to be another sharp spike in political donations, amid a political race already smashing fundraising records, campaign finance experts said.

"We're easily going to have the first billion-dollar presidential race," said Richard Parker, lecturer in public policy at Harvard University's Kennedy School of Government.

Obama had raised $265.4 million (136 million pounds) from all sources through the end of April, according to the latest analysis of Federal Election Commission records by the Centre for Responsive Politics, a nonpartisan, campaign finance watchdog.

New York Sen. Clinton's total take over the same period was $214.9 million, while Arizona Sen. McCain's was $96.7 million.

"A large number of Clinton donors will now send money to Obama, especially when Sen. Clinton endorses him," said Howard Reiter, head of the University of Connecticut's political science department.

In addition, Reiter said, Obama "is likely to receive a lot of donations from people waiting for the dust to settle."

He is the first black candidate to lead a major U.S. party into a presidential race.

Undecided Democrats and independents who were torn between Obama and Clinton will choose sides and reach for their chequebooks now that the options are clearer, experts said.

Obama "will now be running against someone who is very different from him. ... He and Sen. Clinton were very similar," said Michael Malbin, executive director of the Campaign Finance Institute affiliated with George Washington University.

McCain probably will not be able to raise as much money as Obama, but the Republican won't drown. "He'll be competitive financially," said Malbin, also a professor of political science at the State University of New York at Albany.

OBAMA, CLINTON MERGER

Combining the Obama and Clinton donor networks will pose interesting political problems, Parker said.

Much of the New York Democrat's money came from big-ticket backers, like Wall Street. Obama has taken in plenty of money from investment banks and lawyers as well.

But he also he has a formidable Internet fund-raising machine that relies on middle-class Americans. That could mean he won't be beholden to Goldman Sachs and JPMorgan Chase, for instance, Parker said.

"It's going to be an interesting tension to try to meld the Clinton and Obama organizations," Parker said.

More of Obama's campaign funds have come from lawyers than any other segment of the economy, which is typical.

Four of his five biggest contributors have been employees

of investment banks Goldman Sachs, UBS, JPMorgan Chase and Citigroup, as well as their family members and affiliated political action committees.

Lehman Brothers and Morgan Stanley employees also rank among Obama's leading campaign donors.

(Editing by Stacey Joyce)