According to polls and pundits, voters will soon turn the keys to the House and possibly the Senate over to the Democrats. Less easy to forecast: what that would mean for foreign policy in general and the war in Iraq in particular.

My optimistic scenario is that Democrats, given power, also will assume responsibility -- and that the White House will open its doors to those willing to work on a bipartisan basis to solve the historic challenges America faces.

A key player could be Sen. Joseph Lieberman. His convictions on Iraq cost him the Democratic primary in Connecticut. But Lieberman now appears poised to win the general election running as an independent against a left-wing, "insurgent" Democrat and a lackluster Republican. Lieberman has proposed forming a "bipartisan Iraq working group" in Congress early next year.

It would include top members of the committees overseeing foreign policy. One might suggest he also invite some of the freshmen congressmen whose victories will have brought the Democratic Party back from the wilderness. Many of these politicians are from "red states" and have been running on fairly conservative platforms. Though critical of the administration's war effort, they may be sober enough to understand that if America sinks in Iraq it will not be only Captain Bush and his crew who will drown.

Now here's my pessimistic scenario: The congressional Democrats who end up holding the reins are those favored by the left-wing base and blogs, such as Rep. John Murtha --who has said America is "more dangerous to world peace than Iran or North Korea," and Rep. John Conyers, who has made it clear his agenda will include repealing vital counter-terrorism laws (e.g. the Patriot Act) and initiating impeachment proceedings against the president.

Among those inspiring such Democrats is Retired Lt. Gen. William E. Odom, a Yale professor who this week wrote an op-ed in the Los Angeles Times explicitly calling for a policy of "cutting and running" from Iraq. The U.S. also should drop its "resistance to Iran's nuclear weapons program," Odom wrote. "This will be as distasteful for U.S. leaders as cutting and running, but it is no less essential."

There is a huge gap between such Petainist positions and Bush's goal of "victory" -- defined as Iraq's transformation into a beacon for the Middle East. If moderate Democrats prevail and seek common ground with the White House, the mission ought to be to develop policies that can salvage as much as possible from the difficult situation in Iraq, policies that stand a chance of averting what Lieberman has termed "defeat and disaster."

Among the outcomes that need to be prevented: al-Qaeda in Iraq setting up permanent bases in the Sunni regions of the west; Iran controlling the Shia regions of the south; Saddam Hussein released from his cell and restored to his palaces; the pro-American Kurds coming under attack by hostile neighbors; militant Islamist terrorists using additional waves of suicide-bombings of innocent civilians to drive Americans out of Afghanistan and also to take over Jordan, Bangladesh and other countries.

Additionally, despite Odom's strange delusions, it would be catastrophic if the militant Islamist, terrorist-sponsoring, oil-rich and feverishly anti-American regime in Iran were to obtain nuclear weapons.

Both Democrats and the Bush administration would benefit from working cooperatively and successfully on these issues. Bipartisan support would make it easier for the president to take bolder initiatives and rally the public behind them. Democrats would have a chance to reclaim the standing they enjoyed on national security under such presidents as Roosevelt, Truman and Kennedy.

It is only in recent years that Democrats developed a reputation for fecklessness when it comes to foreign policy and defense. Largely as a result, from Lyndon Johnson's departure from the Oval Office in 1969 to Bill Clinton's post-Cold War return there in 1992, a Democrat served as president for only one term -- and that was thanks to a Republican scandal. The Carter administration, by responding ineffectually to Iran's Islamist revolution, further tarnished the Democratic brand on foreign policy, a fact that has plagued Democratic presidential candidates for more than a generation.

If, over the next two years, Democrats can reestablish their hard power credentials, their chances to re-take the White House in 2008 will improve markedly. If they fail to accomplish that, their best hope is that Republicans continue to over-promise, under-achieve and get caught in sundry scandals and embarrassments. (Not that that's such a long shot.)