The notion that "politics stops at the water's edge" hasn't prevailed for much of U.S. history, but the current level of foreign-policy partisanship is dangerous to national security.

Instead of uniting in the face of mortal danger -- the threat of Islamic radicals intent on acquiring nuclear weapons -- Republicans and Democrats are busy savaging each other.

When the United Kingdom broke up the plot to blow up U.S.-bound airliners over the Atlantic Ocean, it should have been a reminder of our common threat.

Instead, Democrats blasted the Bush administration for wasting resources on Iraq while Republicans sought to prove once again that Democrats are weak on terrorism.

In the meantime, the Islamic radical group Hezbollah has won a public relations victory against Israel and a strategic victory over the government of Lebanon -- and Iran and Syria, are cheering.

The fighting in Lebanon diverted world attention from Iran's nuclear program, which proceeds, and served to divide a coalition of Arabs, Europeans and Americans determined to resist the spread of Iranian influence.

It's probably impossible, on the merits and in an election year, to achieve unity on all the policies necessary to cope with the multi-phased threat facing the West. But it's a time for sober, serious debate -- not name-calling and point-scoring.

But that's what we've got. Senate Minority Leader Harry Reid, D-Nev., observed that "five years after 9/11, al-Qaida has morphed into a global franchise operation, terror attacks have increased sharply across the world and the president has shut down the program designed to catch bin Laden." Vice President Dick Cheney alleged that antiwar Democrat Ned Lamont's primary election victory over Sen. Joe Lieberman, D-Conn., had "encouraged al-Qaida types."

Farther down the political food chain, New York GOP Senate contender John Spencer is running an ad pairing Sen. Hillary Rodham Clinton's (D) picture with one of Osama bin Laden to accuse her of "playing politics with national security."

Bush already stands as the most polarizing president in recent history and his most polarizing policy of all is the Iraq war. The latest Gallup Poll shows 84 percent of Republicans still believe it was not a mistake to start the war, whereas 82 percent of Democrats believe it was, along with 54 percent of all voters.

Foreign policy has often divided Americans. Only World War II was widely seen as a "good war."

The conflict with Islamic radicalism should be seen in the same light, so profound are the potential consequences -- the use of weapons of mass destruction in the name of conquering the world for jihad.

In 2006, and for as long as the war against terrorism lasts, our leaders should be judged on how they contribute to defeating the radical enemy.

They should be judged on what ideas they produce for prevailing in Iraq; on how to thwart Iran's drive for nuclear weapons; and on how to win the hearts and minds of moderate Muslims, and keep the allegiance of Arab-Americans and Muslim-Americans, while still "profiling" terrorists.

Republicans should be able to say they are better at fighting terrorism without implying that Democrats are disloyal. And Democrats should be able to challenge Bush on Iraq and terrorism policy without claiming (as New York Times columnist Paul Krugman did this week) that "from the very beginning," the administration "saw the terrorist threat not as a problem to be solved, but as a political opportunity to be exploited."

Anyone who does not believe that we Americans are all in this together should heed the words and deeds of al-Qaida leaders, who hold that using weapons of mass destruction against infidels is God's work.

(Morton Kondracke is executive editor of Roll Call, the newspaper of Capitol Hill.)