The year 2003 reminds me of the movie serials I used to watch as a kid at Saturday matinees, where you waited eagerly for the final installment that would tell you how it all came out.

In the last 12 months, we’ve viewed several episodes of “Iraq: The U.S. War to Remake the World.” But the serial is far from over. The heart of the story — why the lead character, George W. Bush, chose to go to war — remains unclear, since subsequent installments keep revising the reasons.

As for how the saga ends, you won’t find out until 2004, or way beyond that.

But the tale so far offers clues. So let’s reprise what we now know as 2003 ends.

Installment One: The Bush team determines to oust Saddam Hussein, with or without allied or U.N. backing. The Bushies claim Saddam has weapons of mass destruction that might be handed off to terrorists. They hype specious data that the Iraqi leader is about to produce nukes. They hint at serious ties between Saddam and al-Qaida even though they have no proof.

The president doesn’t trust the American public enough to lay out the only rationale for war: The Saddam threat is real, but not to us, and not in the short term. If shaky U.N. sanctions are ultimately dropped, Saddam might once again threaten his neighbors. Perhaps the White House doesn’t think the real threat is sexy enough, so prevarication is needed. On that basis, we go to war.

Installment Two: America wins swiftly.

Installment Three: The shocking lack of prewar planning for the post-Saddam era creates a dangerous mess.

Turns out that the intellectual architects of the war, such as Deputy Secretary of Defense Paul Wolfowitz, thought the aftermath would be easy. He believed postwar Iraq would resemble postwar France, where we drove out the Nazis and French (read “Iraqi”) exiles returned to establish democracy. So Pentagon postwar planning for Iraq began only a few weeks before the fighting.

U.S civilians tasked with running Iraq arrived without phones or translators. They got little help from a Pentagon uninterested in nation-building. The ensuing chaos soured many Iraqis on the U.S. presence.

Installment Four: U.S. inspectors find no weapons of mass destruction. No problem. The administration shifts the rationale for war: Now the goal is to create Mideast democracy with Iraq as a role model. This will change the political and religious climate that has fostered terrorism.

What a revolutionary goal in a region where the Iraq war has increased youthful hatred of the West; where democracy is often viewed as a Western export; where the Israeli-Palestinian conflict still roils public opinion. In many Mideast countries, a free vote would usher in Islamist rule. Can America win such a struggle?

The next installments of this saga won’t be ready until 2004. But it’s not too early to speculate. As in movies with alternative endings, one could write opposing scenarios for the finale of this war tale.

Installment Five, first version: In full messianic mode, the Bush team tries to mold Iraqi democracy to our model. The planned June 2004 turnover of sovereignty to Iraqis is rigged; the new Iraqi government is actually selected by U.S. officials. This alienates the majority Iraqi Shiites, who want real elections. It fails to win over the angry Sunni minority, who need to be offered a genuine political foothold to woo them away from insurgency. Iraqi violence increases. The Iraq model fails to inspire beleaguered Mideast democrats or intimidate regional autocrats and rogue states.

Installment Five, second version: In realistic mode, the Bush team tones down its aspirations and recognizes regional limits. It lets Iraqis elect a legitimate government, even though the result may not be wholly pro-American.

It reaches out to Iraq’s neighbors. The goodwill engendered by earthquake aid to Iranians is used to renew a dialogue with Tehran to undercut to prevent Iranian meddling in Iraq. “Axis of evil” daydreams about invading more Mideast nations fade.

Modest stability and a degree of representation in Baghdad are a great advance, even if they are decades from real democracy. A legitimate Iraqi government provides a Mideast model of sorts. Meantime, Bush makes a serious effort to galvanize an Israeli-Palestinian peace based on the Geneva Accord — not the flawed Sharon plan. Mideast publics take note, as do weapons proliferators.

This is the ending we should all be hoping for in 2004.

Trudy Rubin is a columnist and editorial-board member for the Philadelphia Inquirer.