(CNN) One misguided decision can partially offset a whole lot of good ones, and so it is with "Watergate," a comprehensive trip into the way-back machine, which makes the serious misstep of dramatically reenacting the Nixon tapes. Receiving a theatrical run in advance of a three-night stand on History channel, it's still worthwhile as a dense look at America's past -- and in terms of checking executive actions, perhaps a preview of its future.

Director Charles Ferguson ("Inside Job") interviews a who's who of key Watergate figures, providing a deep dive into Richard Nixon's flawed psyche, which allowed the abuses of power and subsequent obstruction of justice that eventually forced his resignation in 1974. But if the hybrid approach he employs by weaving in the dramatized scenes isn't quite a cancer on his documentary, it's a drag on an otherwise first-rate account.

In terms of an insider's guide go what transpired, one could hardly ask for a better cast of characters, including reporters Carl Bernstein and Bob Woodward, Dan Rather, Nixon White House aides John Dean and Pat Buchanan, Pentagon Papers whistleblower Daniel Elsberg, the late John McCain, and former members of the Senate Watergate Committee, like Lowell Weicker, to name a few.

But then Ferguson mucks that up by having actors perform the taped Oval Office meetings, with Douglas Hodge as Nixon, complete with sweaty upper lip and at-times slurred, drunken delivery.

The problem is that we've seen plenty of dramatic portrayals of this period, from "All the President's Men" to "Nixon" to "The Final Days" to, most recently, "The Post." Because there's such a rich treasure trove of video and archival material, mixing actors in with the actual footage of Nixon -- uttering by-now indelible phrases like "I'm not a crook" -- merely muddies the waters in wholly unnecessary, neither-fish-nor-fowl fashion.

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