It would seem a minor whodunit for a small suburb: On the first day of school in September, three access lanes leading from Fort Lee, N.J., streets to the George Washington Bridge were unexpectedly and mysteriously shut down. Cars backed up, the town turned into a parking lot, half-hour bridge commutes stretched into four hours, buses and children were late for school, and emergency workers could not respond quickly to the day’s events, which included a missing toddler, a cardiac arrest and a car driving into a building.

But the George Washington Bridge is the world’s busiest, and New Jersey is led by one of the nation’s most pugnacious and prominent politicians, Gov. Chris Christie — who also happens to appoint the people who control the bridge.

So the unfolding story of the lane closings has become something of a cause célèbre, resulting in a hearing before the New Jersey Legislature on Monday, as well as a window into the proudly aggressive and often secretive dealings of Mr. Christie’s team.

The mayor of Fort Lee, a Democrat, complained in a letter in September that the lane closings were “punitive” — Mr. Christie, a Republican, was leaning heavily on Democratic mayors to endorse him for re-election so he could present himself as a presidential candidate with bipartisan appeal, but the mayor was not going along.