The WikiLeaks documents on the Afghanistan war have brought suggestions such as this one (from The New York Times, the newspaper that published both) that they represent "the Pentagon Papers of our time." Not quite.

Here are a few quick thoughts on the analogy:

What's importantly similar to the Pentagon Papers

The greatest similarity between the WikiLeaks trove and the Pentagon Papers is that the documents end before the current administration's policy began. In political terms, that is hugely important.

The Pentagon Papers, of course, were a secret study, commissioned during the Lyndon Johnson administration by Secretary of Defense Robert McNamara. The period under study ended in 1968, and the papers were not made public until 1971. Johnson left office in 1969, and was succeeded by a president of the opposing party, Richard Nixon. Nixon promised a shift in Vietnam policy, and while his policy did not differ as much in practice as he had hinted that it would while campaigning, he was not held responsible, by most voters, for the deepening mess of the Johnson years.

In the current case, as the White House has repeatedly pointed out in the last 18 hours, the papers end before President Barack Obama's announcement last year of an Afghanistan policy that departed from that of President George W. Bush. (That policy, of course, has centered on significantly increasing the number of troops, and focusing more on counterinsurgency.)

What's crucially different from the Pentagon Papers

In terms of important disclosures, it's not even close, with the historical importance of today's documents likely to be relatively minor, and that of the Pentagon Papers enormous. The most significant revelations today include the Taliban's limited use of heat-seeking missiles (which had been previously reported, though little-noticed), and the Pakistani intelligence service's constant double-dealing and occasional cooperation with the Taliban (long the subject of news stories, and even of some official complaints).

In 1971, in contrast, the Pentagon Papers revealed a host of important discrepancies between the public posture of the U.S. government with respect to Vietnam and the truth -- from the Truman administration, through the times of Presidents Eisenhower, Kennedy and Johnson.

These included Johnson's dissembling during the 1964 presidential campaign and in the run-up to the key decision in 1965 to send large numbers of combat troops, as well as confirmation of U.S. involvement in the 1963 coup against South Vietnamese premier Ngo Dinh Diem. And perhaps most famously, was the evidence that the administration had decided to escalate the war before the 1964 Tonkin Gulf Resolution gave it the authority to do so.

There are many reasons for the differences between these two troves of documents, but perhaps the most important is that today's documents provide a "ground-level" view of the war, while the Pentagon Papers offered a classic "top-down" perspective. Wars are fought on the ground, and the perspective such a view provides can be invaluable. But many of a war's key secrets, especially in political terms, are generated at the top.

The real impact of the Pentagon Papers

There is a lot of loose talk today about the impact of the Pentagon Papers. Much of it, I suspect, stems from this in the Wikipedia entry: "The revelations widened the credibility gap between the US government and the people, hurting President Richard Nixon's war effort." In fact, a much stronger argument can be made for the proposition that there was almost no impact on the Nixon administration's ability to conduct the war as it wished. Nixon's policy continued apace, through the peace negotiations of 1972 (during a presidential campaign!), continuing with the Christmas 1972 bombing of Hanoi and Haiphong harbor, and including the January 1973 peace accords.

The great antiwar demonstrations that many of us recall -- the March on Washington, the student Moratorium, Kent State -- all took place before the publication of the papers. Nixon invaded Cambodia 14 months earlier. What happened after the papers was that Nixon coasted to re-election by one of the largest majorities in American history, and his adviser Henry Kissinger won a share of the Nobel Peace Prize for "ending" the Vietnam War.

That said, there were profound effects from the release of the Pentagon Papers. They came in how the Nixon administration responded to the leak and the publication of the papers. First, the administration went to court and soon suffered, in the Supreme Court, the most significant defeat for the executive branch in the national security field since Lincoln's suspension of habeas corpus was struck down in 1866 (i.e. after the Civil War ended and after Lincoln was killed).

Beyond the legal battle, Nixon and his henchmen launched the "plumbers" operation (to stem more leaks) and thus set off down the road that led to Watergate -- and all that followed. These became the central American political events of the 1970s, and hugely weakened the presidency, with consequences including the Gerald Ford administration's powerlessness with Congress when the North Vietnamese violated the peace accords in 1975.

How the Obama administration will react today is, of course, still emerging, and already being debated. But where Nixon brought suit and ordered burglaries, I find an early sign in this from the New York Times Washington bureau chief, Dean Baquet:

"I did in fact go the White House and lay out for them what we had," Baquet said. "We did it to give them the opportunity to comment and react. They did. They also praised us for the way we handled it, for giving them a chance to discuss it, and for handling the information with care. And for being responsible."