A Matter of History; Legacy: Why do our leaders seem so small compared with the World War II generation? Wait for the secret memos to come out, and Bush and Blair may someday look much larger than they do now.

Byline: Sir Martin Gilbert (Martin Gilbert is a leading historian. Among his books are "Churchill: A Life" and "Israel: A History.")

People often ask how history will remember our generation of leaders in comparison with the second world war leaders Winston Churchill and Franklin Delano Roosevelt. Many comment that today's leaders look small compared with the giants of the past. This is, I believe, a misconception. In their day, both Churchill and Roosevelt were frequently criticized, often savagely, by their fellow countrymen, including legislators who had little knowledge of the behind-the-scenes reality of the war.

The passage of time both elevates and reduces reputations. Today there is a cult of Churchill, particularly in the United States, but also far greater scholarly criticism, which regards him, increasingly, as a flawed war leader. The same is true of Roosevelt: his recent biographers are constantly revealing--to their satisfaction, at least--feet of clay.

Although it can easily be argued that George W. Bush and Tony Blair face a far lesser challenge than Roosevelt and Churchill did--that the war on terror is not a third world war--they may well, with the passage of time and the opening of the archives, join the ranks of Roosevelt and Churchill. Their own societies are too divided today to deliver a calm judgment, and many of their achievements may be in the future: when Iraq has a stable democracy, with Al Qaeda neutralized, and when Israel and the Palestinian Authority are independent democracies, living side by side in constructive economic cooperation. If they can move this latter aim, to which Bush and Blair pledged themselves on Nov. 12, it will be a leadership achievement of historic proportions.

The leadership of Churchill and Roosevelt in the second world war was conducted in such a way that only many years after the war were its true parameters clear. This is also true of Bush and Blair: only when the secret telegrams and conversations become available will we really know who did what, who influenced whom. Before the war against Saddam Hussein, Blair's emissary Sir David Manning was flying almost weekly to Washington, but it may be many years before we know what decisions were reached during these journeys. Any accurate assessment of Bush and Blair must wait, perhaps a decade or longer, until the record can be scrutinized.

Yet some comparisons are already clear.

Controversy was never absent in the second world war, either. When Churchill became prime minister in May 1940, he had to struggle to overcome defeatists who urged a negotiated peace with Hitler. Similarly, Blair overcame opposition from within his own Labour Party to the war in Iraq, prevailing over the doubters in parliamentary debate on the eve of the Iraq war.