NEW BRUNSWICK, NJ -  Legendary journalist Bob Woodward sees President Donald Trump becoming more and more isolated, unwilling to listen to advisers and making impulsive decisions based on false information and assumptions.

"I think it's a national emergency in the White House," Woodward said when he appeared Monday night at the State Theatre in New Brunswick.

In a freewheeling exchange with former New Jersey Gov. Christie Whitman, who served as moderator, Woodward spoke about his career, from breaking stories on the 1970s Watergate scandal that forced Richard Nixon to resign as president, up to the Trump administration and Woodward's latest book, "FEAR: Trump in the White House."

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Asked about comparisons between the investigations of those two presidents, Woodward said there are many, but he noted that Nixon was proven to have been a criminal, in large part because of the tape recordings of his oval office conversations.

Special Prosecutor Robert Mueller, who is investigating the current president, has given no indication of whether he has evidence of crimes, as were found against Nixon.

"Maybe Mueller has done that and maybe he will expose Trump in a dramatic way," Woodward said, then quickly added, "maybe he won't."

He described Mueller as a tenacious prosecutor who would go after he any crime he uncovers. Mueller, he said, has been called the "mattress tag prosecutor," because people who know him say he would prosecute somebody for tearing off a tag commonly found on mattresses that says "do not remove."

The author of 19 books who has covered nine presidents, Woodward said that while news reporters did good work covering the last presidential election, they could have done more.

"I personally fault myself for not getting Trump's tax returns," he said. Reporters often gauge a politician's mindset through his voting record, Woodward said, but sources in the IRS have indicated that Trump's "tax returns are a roadmap to who he is."

Woodward said he recorded all his sources for the book, "Fear" talking with some people for hours over several days, but always going to their homes at night when they felt more comfortable.

In a lighter moment of the night, Woodward asked Whitman, "Did anyone come knocking at your door at night while you were governor?"

"No," said Whitman, "there was never (a reporter) at my door."

"For shame," the famed journalist said, jokingly chiding the failure of reporters to seek her out that way.

He said he could not predict if Trump would be re-elected, but added that the mid-elections, in which Democrats won a majority of the seats in the House of Representative, may foreshadow events for the 2020 presidential election.

Regardless of the election, he said Nixon may have shown how Trump could escape prosecution. Nixon appointed Gerald Ford as vice president, and when Nixon left office, Ford became president and pardoned Nixon.

"History could provide Trump with a map," Woodward said.

Whitman quickly responded that Trump "doesn't read history."