(Opinion crossposted from Brainstorm)

On September 2, at the time of the Republican convention, I was pinned down for a prediction during a talk I gave at the University of Mississippi. Here’s what I said: “Obama will win the popular vote by 5 or 6 points and the electoral college with roughly 350 or 360 votes.”

If anything, I was too cautious.

Barack Obama seems headed for a victory in three weeks that will set the stage for an outbreak of new programmatic activity resembling those that followed Woodrow Wilson’s election in 1912, Franklin D. Roosevelt’s in 1932, Lyndon B. Johnson’s in 1964, and Ronald Reagan’s in 1980. Each of these candidates won what Vanderbilt political scientist Erwin Hargrove and I called an “empowering election” in our 1984 book, Presidents, Politics, and Policy.

Empowering elections are rare — only four in the last 100 years. They share three defining characteristics: The victor runs a change-oriented campaign (whether specific in content, like Wilson’s and Reagan’s, or just thematic in tone, like FDR’s and Obama’s), wins in a landslide (at least 2-to-1 in the electoral college), and sees his party make unusually large gains in the accompanying congressional elections. Down-ballot gains for the Democratic Party are especially likely this year in the Senate, where the GOP has twice as many seats at stake as the Democrats. But, even in the House, Democrats are poised to add one or two dozen new seats, a remarkable outcome considering the gains they made in 2006.

Empowering elections also have a well-defined consequence: They create the conditions for a dramatic burst of new legislation in Washington that markedly changes the role of the federal government in American society. One can only hope that Obama is thinking as much about what he’ll do after inauguration day as he is about getting to election day.