Intelligence efforts have given the United States a decisive edge during many wars. But twice in our history clandestine information has driven us into a war.

While the press bombards us daily with doubts over the existence of weapons of mass destruction (search) in Iraq, we should step back to consider the effects of a secret revealed early in the last century. That eye opener also exposed a credible security threat at the time, and its revelation immediately hurled United States troops into the maws of a monumental world conflict.

Eventually we may know if Iraq still has WMD hidden either in that country or in another, or even if Saddam Hussein once had them in great number. But today we know for certain that the  threat that plunged the United States into the First World War did not materialize.

Nevertheless, its implications alone were enough to drive the country at full speed into what was once called The Great War (search).

On New Year's Day 1917, World War I continued to decimate young European troops mired in the trenches, as it had since hostilities began in August 1914. In the first month of that New Year, German Foreign Minister Arthur Zimmermann (search) cabled a coded message to the President of Mexico, Venustiano Carranza (search), who recently had all but offered the use of his coastline for German submarine bases.

The Zimmermann Telegram (search), as it came to be known, proposed that in the event the U.S. were to enter the war on the side of France and Great Britain, Germany would establish an alliance with Mexico in both war and in peace.

And if Carranza were to accept the pact, Germany would help him reconquer territory his country had lost to the United State many decades before—all of Texas, New Mexico, and Arizona, to be exact-and maybe invite Japan to join them.

British intelligence intercepted the transmission and gave it to cryptographers. But to avoid revealing the operation that produced their covert coup, and to time its propaganda value, the British waited until late February before handing the decoded text to President Woodrow Wilson. By then the Kaiser (search) had expanded his submarine attacks and the U.S. severed diplomatic relations with his country in response.

The fuse was set to ignite. And in releasing the telegram to the press President Woodrow Wilson (search) struck the match.

In March 1917, virtually every newspaper in the country carried its contents. Public fury exploded in Congress in early April when, without fear of what could erupt on our southern border, the U.S. declared war on Germany and its allies. But the potential Mexican-German axis never marched arm-in-arm across the Rio Grande, after all.

It was neither Germans torpedoing the Lusitania (search) two years earlier, nor President Wilson calling for "a war to end all wars" that unleashed the expedition whose efforts--when the war ended Nov. 11, 1918--resulted in more than 48,000 Americans killed in action, another 27,000 dead from related causes, and 237,000 wounded. It was the righteous anger of Americans willing to sacrifice their young in answer to the documented "smoking gun" of the Kaiser's hostile intent toward them. It was also their unspoken reply to The Zimmermann Telegram: We refuse to surrender even one clod of soil in our Southwest that Americans died on to acquire.

President Woodrow Wilson did not act alone to thwart international thuggery, just as it was not President George W. Bush alone who spoiled any chance Saddam Hussein might have had to play a role in raining atrocities on us from beyond our borders. In each case a president had the country's consent—loud and vocal for Wilson, solemn and grim for Bush—to activate its voice of outrage.

Thus in March of 2003, America did not sit paralyzed in fear waiting to see if the alleged Iraqi threat would metastasize into a plague fatally penetrating not only our borders but a significant part of the planet as well.

Spurred by the raw memory of 3,000 helpless victims unaware being pulverized on a sunny September morning in the towers of the World Trade Center, the Pentagon, and at the bottom of a 50-foot crater in Pennsylvania, a majority of our elected representatives backed President Bush's resolution to summon once again the sacrifice of the young.

Behind our drive into Baghdad was the quiet dirge of unresolved bereavement reverberating in the air a year and a half after the four-pronged attack.

Following the assassination of Abraham Lincoln in 1865, from beneath the shroud draping the northern half of the nation, Herman Melville found words to depict the relentless ability of Americans to confront evil and attempt to vanquish it, while shouldering the overbearing sorrow that seeks retribution and demands redress:

"There is sobbing of the strong,
And a pall upon the land;
But the People in their weeping
Bare the iron hand:
Beware the People weeping
When they bare the iron hand."