(CNN)  -- The cool of Barack Obama was very much on display on a warm day in Boston's Christopher Columbus Park during the summer of 2004. John Kerry, right, and Obama confer at the 2004 DNC, where Obama wowed the crowd with his keynote address. It was going to be a big day for the Democratic nominee for the U.S. Senate from Illinois. In a few hours, on that night, July 27, 2004, he was to give the keynote address to the Democratic National Convention at the Fleet Center about a mile away. But as he gave a lunchtime speech on environmental policy to a leisurely crowd of about 100 people at the green space on Boston Harbor, he was relaxed and loose, seemingly unconcerned about what was ahead.
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Writer rode with Obama on his way to give keynote address at 2004 DNC
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Obama's keynote electrified the nation, emphasized unity
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Candidate John Kerry took a chance giving keynote to lesser-known Obama
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Obama calm: Said the pressure "nothing compared to folks ... getting laid off"
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In the front passenger seat of the van, the rail-thin @placeholder, obviously hungry (he later told me he'd lost eight pounds since the beginning of the campaign), chewed on a sandwich and joked with the other passengers as I peppered him with questions during the 20-minute ride.
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Not even @placeholder knows for sure how he landed the keynote slot.
John Kerry
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He didn't meet 2004 Democratic presidential candidate John Kerry until the Illinois primary was over, he recalls; he spoke at a @placeholder fundraiser but didn't know he'd be giving a speech at the DNC until weeks later.
John Kerry
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"It's @placeholder kind of looking at him [at the fundraiser] and picking up tricks from the rookie," Mendell said.
Fleet Center
He gave a hint of those words in the van on the way to the @placeholder.