On Sept. 1, 1939, Hitler's panzers smashed into Poland. Two days later, an anguished Neville Chamberlain declared war, the most awful war in all of history.

Was the war inevitable? No. No war is inevitable until it has begun. Was it a necessary war? Hearken to Churchill:

"One day, President Roosevelt told me that he was asking publicly for suggestions about what the war should be called. I said at once, 'The Unnecessary War.' There never was a war more easy to stop than that which has just wrecked what was left of the world ... ."

But if the war need not have happened, what caused it?

Let us go back to Munich.

On Sept. 30, 1938, at Munich, Chamberlain signed away the Sudetenland rather than fight to keep 3.5 million Germans under a Czech rule imposed upon them at the Paris peace conference in violation of Wilson's principle of self-determination.

Why did Britain not fight?

Because Britain had no alliance with Prague and Chamberlain did not "give two hoots" who ruled the Sudetenland. Also, Britain had no draft, no divisions to send to France, no Spitfires, no support from America or her dominions, no ally save France, who had been told that, if war came, the United States would not deliver the planes France had purchased.

U.S. neutrality laws forbade it.

In his meetings with Chamberlain, Hitler had warned that Poland and Hungary would also be entering claims for ancestral lands ceded to the Czechs at Paris in 1919.

Thus, after Munich, Warsaw had seized coal-rich Teschen, which held tens of thousands of Poles. Hungary, in the "Vienna Award" of Nov. 2, 1938, got back lands in Slovakia and Ruthenia where Hungarians were the majority and Budapest had ruled before 1919.

Neither Britain nor France resisted these border revisions.

Came then March 1939, when Czechoslovakia began to crumble.

On March 10, to crush a Slovakian push for independence, Czech President Emil Hacha ousted Slovak Prime Minister Father Tiso, occupied Bratislava and installed a pro-Prague regime.

On March 11, Tiso fled to Vienna and appealed to Berlin.

On March 13, Tiso met Hitler, who told him that if he did not declare independence immediately, Germany would not interfere with Hungary's re-annexation of Slovakia. Budapest was moving troops to the border.

On March 14, Slovakia declared independence. Ruthenia followed, dissolving what was left of Czechoslovakia.

Adm. Horthy, told by Hitler he could re-annex Ruthenia but must keep his hands off Slovakia, occupied Ruthenia.

Hacha now asked to meet with Hitler to get the same guarantee of independence Slovakia had gotten. But Hitler bullied Hacha into making the Czech remnant a protectorate of Germany.

Thus, six months after Munich, the Germans of Czechoslovakia were where they wished to be, under German rule. The Poles were under Polish rule. The Hungarians were under Hungarian rule. And the Slovaks were under Slovak rule in their new nation.

But 500,000 Ruthenians were back under Budapest, and 7 million Czechs were back under German rule -- this time Berlin, not Vienna.

Ethnonationalism had torn Czechoslovakia apart as it had the parent Hapsburg Empire. Yet, no vital British interest was imperiled.

And though Hitler had used brutal Bismarckian diplomacy, not force, Chamberlain was humiliated. The altarpiece of his career, the Munich accord, was now an object of mockery.

Made a fool of by Hitler, baited by his backbenchers, goaded by Lord Halifax, facing a vote of no confidence, on March 31, 1939, Chamberlain made the greatest blunder in British diplomatic history. He handed an unsolicited war guarantee to the Polish colonels who had just bitten off a chunk of Czechoslovakia.

Lunacy, raged Lloyd George, who was echoed by British leaders and almost every historian since.

With the British Empire behind it, Warsaw now refused even to discuss a return of Danzig, the Baltic town, 95 percent German, which even Chamberlain thought should be returned.

Hitler did not want a war with Poland. Had he wanted war, he would have demanded the return of the entire Polish Corridor taken from Germany in 1919. He wanted Danzig back and Poland as an ally in his anti-Comintern Pact. Nor did he want war with a Britain he admired and always saw as a natural ally.

Nor did he want war with France, or he would have demanded the return of Alsace.

But Hitler was out on a limb with Danzig and could not crawl back.

Repeatedly, Hitler tried to negotiate Danzig. Repeatedly, the Poles rebuffed him. Seeing the Allies courting Josef Stalin, Hitler decided to cut his own deal with the detested Bolsheviks and settle the Polish issue by force.

Though Britain had no plans to aid Poland, no intention of aiding Poland and would do nothing to aid Poland -- Churchill would cede half that nation to Stalin and the other half to Stalin's stooges -- Britain declared war for Poland.

The most awful war in all of history followed, which would bankrupt Britain, bring down her empire and bring Stalin's Red Army into Prague, Berlin and Vienna. But Hitler was dead and Germany in ashes.

Cost: 50 million lives. "But 'twas a famous victory."