WASHINGTON (AP) - So much can change in four years.
Some 16 million babies have been born in the United States since 2008, the last year the Democrats and Republicans met to anoint their presidential nominees. Kids who were toddlers then are starting kindergarten now; that year's nervous high school freshmen are beginning college or work, or at least anxiously looking for jobs.
Nearly 10 million Americans have died, including political lights Geraldine Ferraro, Betty Ford and Sen. Edward M. Kennedy, who bade his dramatic convention farewell four years ago.
The Iraq war is over, the war in Afghanistan winding down. Osama bin Laden is dead. Yet Guantanamo Bay still holds 168 terror suspects. And too little has changed in a discouraging economy since 2008.
The political conventions are back to ask again if we, as individuals and as a nation, are better off than we were four years ago. That raises the question, where will we be four years from now?
It's fashionable these days to complain that the party gatherings no longer matter, that they're just phony made-for-TV moments - speeches and sappy films and balloon drops strung together into protracted campaign commercials. That's true, as far as it goes.
The conventions no longer matter in picking presidential nominees. But that's because the choosing moved from the old smoke-filled rooms and rowdy delegate halls to a months-long carnival of democracy: debates and caucuses and primary voting across the country.
The conventions are made for TV. But that means made for all to see, across America and even the world. And the audience now gets to talk back, drafting its own instant platform via Twitter and Facebook and all our other electronic impulses.
The conventions are taxpayer-subsidized political commercials. But if they were only that, few would watch. We've seen too many mean ads already. By now most voters have made up their minds about Barack Obama and Mitt Romney, anyway.
At their best, every four years, these mud-slinging, self-serving, partisan-by-definition displays rise to offer something more: moments that transcend politics.
Together, the two conventions make up a national stock-taking, a pause to remember our roots, figure out who we are and decide what's truly important, without feeling too hokey about it. Like a virtual family reunion, Americans gather around their televisions, computers or smartphones to argue or agree, celebrate the good stuff, mourn our losses and regret our mistakes, to regroup, to look ahead.
The conventions are Barbara Jordan, Jesse Jackson and Obama, their very presence on the podium insisting that the American dream no longer be deferred. And Ferraro and Sarah Palin and Hillary Rodham Clinton, bursting through doors once locked to them.
They are the thousands of Vietnam War protesters chanting outside the 1968 Democratic meeting, who couldn't be silenced by the tear gas and billy clubs of the Chicago police.
They are Robert Kennedy eulogizing the slain president who was also his big brother Jack. Nancy Reagan telling America that its Great Communicator is being hushed by Alzheimer's. Mary Fisher pleading with the nation to come to its senses and find its compassion so her children wouldn't feel ashamed someday to say out loud their mother died of AIDS.
Every four years, the political conventions come along to remind us how wrong we were about some things in the past. And that we know nothing, really, about what's to come.
It's no coincidence that Ronald Reagan, a genius at wielding metaphor, chose to speak at the 1976 GOP convention about what he would write in a time capsule letter to the future.
The conventions are time capsules, lovingly created and then buried in the rush to Election Day.
Dig through past conventions, their speeches and platforms, and you'll find a record not just of Americans' politics but also of their worries and fears, longings and dreams. Not just how the parties gave us Abraham Lincoln and Franklin Roosevelt. But also how passion to do something about slavery and civil rights and women's rights and poverty percolated up from the people and into the convention halls and the White House.
This year's speakers will talk about gay marriage, religious freedom, women's health, the national debt, joblessness. And someone may say something in a way that sticks in the national consciousness and helps build a consensus that one day, in hindsight, will seem blazingly obvious.
Conventions are far from perfect. Too much of their time is wasted on things parochial and elitist and just silly. Not much has changed since Bob Dole summed up the GOP event of 1980: "The introducers spoke longer than the speakers. And the speakers spoke too long."
But what else have we got? Self-consciously triumphant inaugurals, ponderous State of the Union speeches. Debates promise some spontaneity, but they're too narrow, focused only on four candidates.
The conventions are a political Olympics, democracy as spectator sport: Score the best efforts of mayors and governors and senators who might be president someday. Catch those candidates and insiders who claim to hate Washington and loathe politics openly reveling in the raucous, strapping national debate, whatever they prefer to call it. Watch regular folks still willing to turn out, in silly hats and buttons, to cheer for something they believe in.
Sure, it can feel predictable. But that's something to be grateful for - a sign that today's primaries are running fairly smoothly and the nation's many troubles are less devastating than the crises of the past.
Isn't that a good thing so long as it lasts?
After all, the political stage managers won't be able to corral the chaos outside or quiet rising voices within the hall if America faces another crisis as deep as the Depression, another war as despised as Vietnam, another moral test as big as civil rights.