Gov. Arnold Schwarzenegger -- attempting to regain his political footing after a devastating special election defeat this month -- has begun a shakeup of his administration by replacing his chief of staff with a former state Democratic Party official and top adviser to former Gov. Gray Davis, Democratic and Republican sources said Tuesday. The hiring of Susan Kennedy, widely respected by both Democrats and Republicans in Sacramento as a workhorse operative for Davis, is expected to be announced officially as early as today. The move could kick off major protests from conservative Republicans. Appointed by Davis to the California Public...