The night he was elected mayor of Jersey City in May, Steven Fulop got a call from Gov. Chris Christie congratulating him and offering whatever help he could — a pledge that was followed up by texts and emails from Mr. Christie’s campaign and State House aides, who set up a day’s worth of meetings with high-level commissioners in what they promised would be the beginning of a happy relationship.

Two months later, the day Mr. Fulop, a Democrat, relayed word that he could not endorse the governor, a Republican, the meetings were all suddenly off. Documents show that Mr. Christie’s commissioners themselves called to cancel — most within the space of an hour — leaving Jersey City needing to fill its budget without money from the Port Authority of New York and New Jersey, its requests for help with Hurricane Sandy recovery, transportation and other issues falling on deaf ears.

Meanwhile, the Democratic mayor of Harrison, who endorsed Mr. Christie, got $250 million in Port Authority money for a new transit station. The mayor of Union City, another Democratic endorser, got an increase in state aid when bigger cities were being cut off, and $3 million in Port Authority money even though the authority does not operate there. The Democratic county executive in Essex County, who brought along other mayors and black pastors with his endorsement of Mr. Christie, got $7 million in Port Authority money for a park, $4 million in state aid for a vocational school, and personal assistance from Mr. Christie, who served as chairman of a fund-raising campaign for the executive’s beloved zoo. Mr. Christie even showed up to a groundbreaking for a new garage for county vehicles.

Throughout his four years as governor, and particularly in his re-election campaign last year, Mr. Christie has worked his powers of government as an arm of his political operation, awarding favors to those who rewarded his political ambitions and punishing those who got in his way. A system of give and take has always been part of American politics, but the documents from Jersey City, obtained through a Freedom of Information request, demonstrate Mr. Christie’s particularly aggressive embrace of it.