What did New Jersey Gov. Chris Christie know, and when did he know it?
Those questions and others have loomed over the George Washington Bridge lane-closing scandal for three years.
Some of the questions are likely to be answered during the trial of two former Christie allies that begins Monday in federal court in Newark.
Bill Baroni and Bridget Kelly are charged with conspiracy, wire fraud and civil rights violations for allegedly closing access lanes to the bridge and creating traffic gridlock to punish a mayor who didn't endorse Christie.
The most highly anticipated testimony is to come from David Wildstein, who worked with Baroni at the Port Authority of New York and New Jersey, the bridge's operator.
Wildstein pleaded guilty last year.
Christie wasn't charged and has denied knowledge of the alleged plot.