As the U.S. Constitution was being drafted in 1787, Thomas Jefferson wrote that given a choice between “a government without newspapers or newspapers without a government” he would “not hesitate a moment to prefer the latter.”

A free press, it has often been observed since, is the guardian of democracy, with the potential to monitor those in power and let the people they are meant to represent know what they are up to.

That’s what Bob Woodward has famously been doing for more than four decades. The most celebrated investigative journalist of his generation, Woodward has chronicled the inner workings of eight presidential administrations, and helped bring down one in the process.

Woodward – who will be speaking in Portland at the University of Southern Maine Thursday evening – says that despite the recent decline of the newspaper industry and the investigative newsgathering capacity it represents, he’s confident the press will continue to meet its watchdog role, if for no other reason than that it must.

“Newspapers are infrastructure like roads and electrical power lines and so on – it’s vital to the functioning of everything,” Woodward said by telephone from his Washington, D.C., home. “Or we don’t have it – if we miss stories because the resources are so much less – then we will be crippled.

“Government is largely hidden, and I’ve always said the thing to worry about the most is a secret government, which is what will do us in,” he adds. “Democracies die in darkness.”

In Portland, Woodward will be assessing the administrations of presidents from Richard Nixon to Barack Obama, and offering insight into the role leadership played in this year’s presidential campaign. His appearance Thursday is part of the University of Southern Maine’s annual
lecture series on leadership and creativity.

Woodward, 69, started his career in 1970 with a two-week trial at the Washington Post. His editor declined to hire him on account of his inexperience, and Woodward took his first job with the Montgomery Sentinel in D.C.’s Maryland suburbs. A year later, in September 1971, the Post hired him on the metro desk.

Nine months later he and another young reporter, Carl Bernstein, were assigned to report on a burglary at the offices of the Democratic National Committee in the Watergate Hotel. The duo were largely responsible for establishing the involvement of Pres. Richard Nixon’s aides and the effort of the president himself, the Federal Bureau of Investigation, and the Central Intelligence Agency in the coverup.

He and Bernstein followed up with two best-selling books on the scandal, “All The President’s Men” and “The Final Days.” The Post won a Pulizer Prize for their reporting, and another in 2002 for a series of reports on the aftermath of the 9/11 attacks for which Woodward was the lead writer.

Woodward, who is still employed by the Post, has since written 15 books, 12 of which have topped national non-fiction bestseller lists. He’s investigated everything from comedian John Belushi’s fatal drug overdose to the decision-making surrounding the wars in Iraq and Afghanistan under Presidents George W Bush and Barack Obama.

His latest book, “The Price of Power,” provides an inside look at the struggles between Obama and Congressional Republicans over the past four years.

Woodward has often been described, along with longtime rival Seymour Hersh, as the greatest journalist of his generation. “The fraternity of investigative reporters, who make a point of not talking on the record about each other consider Mr. Woodward as a man with access in high places, with all the insight and blinkers that entails,” The New York Times wrote in a 2001 profile of the reporting rivals.

So how does Woodward manage the tension that comes with being given special access to those in power, who are often seeking to put their own spin on these interactions and sometimes demand anonymity in return for the information they provide?

“You manage by checking and getting notes and memos and documents and talking to everyone and then going back again,” said Woodward, who has admitted to not having been skeptical enough about the Bush administration’s evidence for the presence of weapons of mass destruction in Iraq, a thesis his reporting supported before the war.

“You’re not going to get people in intelligence agencies and the White House to talk to you on the record about many things – they just aren’t going to do it,” he adds in defense of the use of anonymous sources, which he’s previously described as “the lifeline to the truth.”

Asked if he thought the rise of the Internet, public databases, and sites like Wikileaks, which can instantly disseminate leaked corporate and government documents, make the watchdog role of the media easier or more difficult, he said the fundamentals of good reporting remain unchanged.

“The internet is a valuable tool, but there are too many people who think it’s a magic lantern,” he said. “I’ve taught journalism classes in college and there’s this assumption that if it happened today, the answers to what happened in the Nixon White House would be on the Internet somewhere, which it wouldn’t, of course. So there may be an overreliance on the Internet.”

“Wikileaks added some important information, but it was oversold,” he adds. “It’s not going to make it into the history books because they were only secret documents, not top secret documents, and didn’t have the same standing in making decisions.”

He doesn’t even like the term “leaks,” which imply that reporters wait passively “sitting around in your pajamas at home or having a cup of coffee at the office until somebody calls you.” Reporters, he says, have to be active and seek information from people before any is forthcoming.

“Whenever the New York Times has a story, that’s a leak,” he jokes at his rival paper’s expense. “When the Washington Post has a good story, that’s aggressive, determined reporting!”

He acknowledges that the decline of papers – the Post has been shedding staff and sections for years – undermines reporters’ ability to dig deep. “We all have to be very aggressive and talk to people and get documents and go back to people again, and that takes money and resources,” he says. “Newspapers are much less than they have ever been because we have less money.”

The primary reason? “Google has taken it all,” he says, a reference to their search engine’s ability to make large amounts of money connecting people to content newspaper companies created, sometimes at great expense.

On Sunday, Woodward was in Waterville to receive Colby College’s annual Eijah Parish Lovejoy award for courageous journalism.

Thursday he’ll be speaking at the University of Southern Maine’s Abromson Center at 7:30 p.m. The talk is entitled “Presidential Decisions and the Role of Leadership in the 2012 Elections” but Woodward says there will be plenty of time for free ranging questions and answers.

Tickets are $20, $10 for students. Seating is first come, first served.