THERE ARE TWO ways to look at presidential legacies:  what historians arrive at after a period of time or what sticks in the minds of the general public.  They come together in President Obama’s case.  Historians and the public agree already that the election of the nation’s first African-American president was a historically significant event. The rest will have to wait.

Reflect for a moment on his immediate predecessors.

George W. Bush will surely be remembered for two wars, cutting taxes, and increased national debt.  In lighter vein, who forgets, “Brownie, you’re doing a heck of a job”?

Bill Clinton is credited with turning the economy around.  This may eclipse his personal misbehavior and impeachment.  Maybe the public has forgiven even if it has not forgotten.

George H.W. Bush presided diplomatically over the end of the Cold War.  He withdrew from Iraq after a brief war costing 140 American deaths and was criticized at the time for not pursuing Saddam Hussein.  These noteworthy achievements, however, are not much discussed, but “read my lips” is still quoted when taxation is the context.

The reopening earlier this year of Ronald Reagan’s and Richard Nixon’s presidential libraries displays a shift in memorialization.

The Reagan exhibits mention the Iran-Contra scandal for the first time, but do so “modestly,” reported The New York Times, while still giving significant space to Nancy Reagan’s dresses.

In contrast, the Nixon Library goes all the way, telling the story of the Watergate scandal in meticulous detail without apology or attempt to explain it away.  It dispassionately raises the question of what and when Nixon knew of the actions of his senior aides.  The historians of the National Archives were clearly in charge, and they have ensured prominent attention to the events that have crowded out almost everything else in our reckoning of the Nixon years. Opening the doors to China just doesn’t seem to compete with Watergate.

Reagan, of course, remains immensely popular, his library drawing nearly four times the visitors of Nixon’s and his eponymous airport in Washington, DC, reminding travelers to and from the nation’s capital of his greatness.  It seems his sins have been forgotten but his charm remains.

So let’s speculate about Obama’s legacy after 32 months.  He began with a mantra of “change” and he has produced some changes.  It’s too soon to tell whether the changes he has been able to effect will remain or be swept away following the next election. He has reduced the population of Guantanamo, forbidden torture, and decided not to enforce the Defense of Marriage Act.  He pushed to cancel Don’t Ask, Don’t Tell and saw to it that Bin Laden was pursued and killed.  Seeking allies in international affairs has been more successful than in Obamacare.  Will he be remembered as “the man who brought (most of) our troops home? Will he be remembered as the change agent he promised or as a compromiser or even as a poor bargainer?

In the end, will he be known only for the historic breakthrough represented by his ancestry or also for the change he rallied voters to support in 2008?  Try putting your prediction in an envelope to be opened in 2012 or later.

Eugenie Beal on the board of the Boston Natural Areas Network, which she helped found in 1977, and a longtime member of the Friends of the Public Garden. She was the first chairwoman of the Boston Conservation Commission, in the 1970s, and the first director of the Boston Environment Department.