Not all presidential elections are equal. It made a lot of difference to America's future that Andrew Jackson beat John Quincy Adams in 1828, that Abraham Lincoln bested Stephen A. Douglas in 1860, and that the 20th century's two most influential presidents, Franklin D. Roosevelt and Ronald Reagan, topped Herbert Hoover and Jimmy Carter, respectively.

Conversely, it's not easy to see that the Republic was decisively affected by James Polk's victory over Henry Clay in 1844, Samuel Tilden's disputed loss to Rutherford B. Hayes in 1876, or the seesaw between Grover Cleveland and Benjamin Harrison in 1884, 1888 and 1892.

The presidential election of 2004 will be another nation-defining fork in the road, a decision with enormous historical consequences.

Beneath the blizzard of rhetoric in recent months, two issues of grave importance have surfaced. The parties, the candidates and the American people seem deeply divided on them; the coveted "middle ground" is going to be hard to find. (Indeed, in the months ahead, there will be several occasions to remember something I first heard in Texas: "The only things in the middle of the road are yellow stripes and dead armadillos.")

The first great issue in this election is the choice between the world imagined by "September 10 people" and the world imagined by "September 12 people."

For September 10 people, what happened on September 11, 2001, is best understood as a crime --- crime on a vast, unprecedented scale, to be sure, but crime nonetheless. On this analysis, the appropriate response to the crime of September 11, and the way to prevent such criminal acts in the future, is through more vigilant and effective police work. Al-Qaeda and similar terrorist organizations should be dealt with in about the same way we deal with international criminal organizations: through enhanced intelligence, interdiction strategies, and the use of international legal institutions. It's not unlikely that September 10 people would find sympathy for their views among many Europeans.

For September 12 people, September 11 was an act of war. Its purpose was what an enemy's purpose always is in war: to break the opponent's will and thus force the opponent to surrender. The appropriate response to an act of war, September 12 people argue, is war: the use of proportionate and discriminate military force to defeat the aggressor and those who support aggression, to deter future predators, and to restore the necessary minimum of order to world affairs. September 12 people agree with September 10 people that the U.S. needs better intelligence-gathering and analysis; but September 12 people are inclined to use that intelligence to take the battle, forcefully, to the enemy, whom they understand as a combatant, not a criminal.

The second great issue underlying the 2004 campaign involves the nature of freedom. Is freedom a means to satisfy personal "needs"? Or does freedom have something to do with moral truth --- with goodness? Is freedom doing things "my way"? Or is freedom doing the right thing for the right reasons in the right way, as a matter of habit (which is another name for "virtue")? Once again, the parties, the candidates, and the nation seem sharply divided here.

The abortion debate, the struggle to define moral and legal boundaries for the development of biotechnology, and the question of a Federal Marriage Amendment are all expressions of this more fundamental division over the nature of freedom. If the argument for freedom as personal willfulness ("my way") prevails, it seems likely that abortion will remain unrestricted, the biotech industry virtually unregulated, and "marriage" will mean, eventually, any configuration of (perhaps any number of) consenting adults. If the argument prevails that freedom means freely choosing what we can know to be morally good, there may be a real chance to accelerate the building of a culture of life in America.

In President Kennedy's last speech, the morning before he died, he told the people of Fort Worth that America is "the keystone in the archway of freedom." Forty years later, the two great questions before the Republic are, what is that freedom, and how shall we defend it? A lot of 21st century history will turn on how the American people answer those questions on November 2.

George Weigel is a senior fellow of the Ethics and Public Policy Center in Washington, D.C.