Gridlock was 'politically motivated', Democrats claim
An email has emerged apparently linking an aide of Republican mayor Chris Christie to a major traffic jam in New Jersey.
The staff member appeared to admit closing bridge lanes in September to punish the Democrat mayor of a New Jersey town who did not endorse Christie's re-election.
In a statement, Mr Christie called the lane closure incident "unacceptable" and vowed to act over the issue.
Politico reporter Elizabeth Titus told BBC Radio 5 live's Up All Night: "It certainly bolstered the case for those Democrats arguing that there was political motivation behind this."