Gov. Chris Christie of New Jersey has built a remarkable brand in Republican politics around a simple message: that his bluster and brashness, grating as they might be, were driven by a desire to transcend partisan rancor and petty politics in the service of the public good.

He would never let himself engage, he once pledged, in the “type of deceitful political trickery that has gone on in this state for much too long.”

But embarrassing revelations about his office’s role in shutting down some access lanes to the George Washington Bridge now imperil that carefully cultivated image. They suggest that the same elbows-out approach that the Christie administration brought to policy battles at the State House may have been deployed for a much less noble end — punishing an entire borough for its mayor’s sin of not embracing the governor’s re-election campaign.

For Mr. Christie, the timing of the blossoming scandal is dreadful, disrupting a highly anticipated plan to present the popular governor to the national electorate as a no-nonsense, bipartisan balm to a deeply divided federal government.