By Jeff Bliss

March 11, Bloomberg

The political passions stirred by the Democratic presidential battle between the possible first black nominee and the possible first woman are also stirring security concerns on the part of the U.S. Secret Service.

The agency began providing protection to candidates earlier this year than in any previous election in response to crowds that have sometimes topped 30,000, a record for the primary season, spokesman Darrin Blackford said.

The excitement of the race pitting Illinois Senator Barack Obama against New York Senator Hillary Clinton ``definitely adds something the Secret Service hasn't seen in a while,'' said Andrew O'Connell, a special agent in the 1990s who is now a managing director at New York-based Fortress Global Investigations and Security Corp.

Besides the fact that Obama is the first black candidate with a chance to win the party nomination, Clinton is a ``polarizing figure'' dating back to her time as first lady, O'Connell said.

Obama, 46, began receiving protection in May 2007, 18 months before the November 2008 election. That was the earliest for any candidate since the practice was instituted following the 1968 assassination of Senator Robert F. Kennedy, shot by Sirhan Sirhan at the Ambassador Hotel in Los Angeles moments after claiming victory in the California primary.

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photo: Barack Obama, U.S. senator from Illinois and 2008 Democratic presidential candidate, greets the crowd at a campaign rally in Concord, New Hampshire, on July 26, 2007 (Photographer: Neal Hamberg/Bloomberg News)