"It can be a very polarizing issue, " said Jason Madrak, chief marketing officer for the Connecticut Health Insurance Exchange, referring to the Boston-New York divide.

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New York - Divide and conquer: That seems to be the motto of the world's third-richest man.

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The divide is typical in citywide races in New York, where the voters are often late to tune in and where strict spending caps force candidates to save advertising money for later.

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