CNN

FROM CNN's Jack Cafferty:

Barack Obama missed another chance last night to knock Hillary Clinton out of the race. He beat her in Iowa, she came back and won New Hampshire. He reeled off eleven wins in a row, she came back and won Ohio and Texas. He had another clear shot at her last night and missed. It raises a question that gets more serious with each passing primary.

Why can't he put her away? Despite outspending Clinton more than 2-to-1 in Pennsylvania and waging a more aggressive campaign in the final days, Obama came up short again with many of the voters who form the traditional base of the Democratic Party. Clinton crushed him among white, blue-collar voters by 69 to 30 percent. She also won older voters, women and whites.

The last 6 weeks have tested Obama in a way he hadn't been before.

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