SACRAMENTO, Calif. (AP) - A closely-watched effort to impose a new tax on tobacco to pay for cancer research in the nation's most populous state has failed by six tenths of a percentage point.
    
The Associated Press determined Friday that California's Proposition 29, backed by cycling legend Lance Armstrong, had failed by about 27,000 votes out 5 million cast.
    
Through a barrage of campaign ads, tobacco companies were able to cut support for the $1-a-pack cigarette tax from a two-thirds majority in March to a dead heat on Election Day.
    
Opponents of the measure raised $47 million to fight it, dramatically outspending supporters, who raised $12 million.
    
Campaign ads sponsored by tobacco companies framed the tax as a government boondoggle and warned that some of the cancer research could be done outside California.

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