"ON THE BRINK OF RUIN"

Christie said he was blindsided by his advisers' involvement and promised to cooperate with various state and federal investigations.

Local newspapers on Saturday said the governor's political career could be doomed if it was proven he knew in advance of the four days of lane closures that caused massive delays for commuters, ambulances and school buses.

The New York Daily News said in an editorial that Christie now "stands on the brink of ruin" if he cannot defend himself against the latest claims.

"In that event, Christie's governorship is over and he should prepare to face a federal criminal probe as a private citizen. Resignation would be a must. Otherwise, impeachment would be a snap," it said.

Charles Stile, a columnist for the Bergen Record, a major New Jersey newspaper, wrote on Saturday that if Wildstein produces evidence that "turns out to be the damning, incontrovertible kind, then Christie's career will be in tatters, if not over."

Shortly after Wildstein's attorney's letter emerged, the Christie administration said it contained nothing to contradict Christie's position that the governor had "no prior knowledge" of the closures.

A bipartisan committee of state lawmakers is investigating the episode, as is the office of Paul Fishman, the U.S. Attorney for New Jersey.