Visit the Virginia Military Institute, in Lexington, and cadets will show you the statue of General George C. Marshall '01 on the edge of the parade ground, and add proudly that Marshall was (and remains) the only soldier ever to win the Nobel Peace Prize (1953). They do this partly because Marshall is VMI's most illustrious graduate, but largely because the prize, when Marshall won it, carried with it a significance and prestige that no longer obtains.

This was painfully obvious last week, when Albert Arnold (Al) Gore Jr.--as the Nobel committee punctiliously identifies him--was awarded this year's Nobel Peace Prize, in conjunction with the U.N.'s Intergovernmental Panel on Climate Change. As if to demonstrate how the foreign press seldom comprehends American politics, the Financial Times of London led the weekend edition with a breathless account of Gore's triumph, headlined "Gore Prize Transforms Debate on Climate."

Al Gore's winning of the Nobel Peace Prize yesterday for his work on climate change is likely to place the issue at the forefront of political debate in the US as the country moves into its presidential election season.

The award, which the former vice-president shares with the United Nations' body of climate experts, follows speculation about a Gore presidential bid.

Up to a point, FT. As it happens, there is no evidence whatsoever that Al Gore's Nobel Peace Prize has had any effect at all on the 2008 Democratic or Republican presidential campaigns, and, according to polls, Democratic voters remain resolutely uninterested in a potential Gore candidacy. Indeed, the laureate himself, who had been coy on the subject, took the occasion to repeat his intention not to seek the presidency next year.

Gore could still change his mind, of course, and global warming might be mentioned at one of those televised debates. But it is symptomatic of the depths to which the Nobel Prize has sunk that its impact this year, such as it is, was inspired by a movie (An Inconvenient Truth) and confined to one phase of U.S. presidential politics. No doubt, a glow will emanate from Gore's capacious skull, and he will savor the ceremony in Oslo and the big gold medal with the profile of Alfred Nobel. But, as if we didn't already know, the Nobel Peace Prize ain't what it used to be.

The problem is that the Nobel Peace Prize, endowed by the conscience-stricken inventor of dynamite, has always had a slightly ambiguous quality about it--unlike, say, the prizes in physics or medicine, even literature.

For many years, it functioned as a kind of gold watch for elder statesmen: the American Elihu Root (1912), Aristide Briand (1926) of France, Britain's stalwart League of Nations advocate Lord Robert Cecil (1937), the Canadian Lester Pearson (1957). There was the occasional miscalculation, of course: The American secretary of state Frank Kellogg (1929) won for his pact, coauthored with the aforementioned Briand, outlawing war as an instrument of national policy--just one decade before the Nazi invasion of Poland. North Vietnam's Le Duc Tho (1973) shared the honors for peace in Indochina, as did Yasser Arafat (1994) for peace in the Middle East. But the prize customarily went to benevolent politicians--Woodrow Wilson (1919), Gustav Stresemann (1926), Cordell Hull (1945)--to well-intentioned people--Jane Addams (1931), Ralph Bunche (1950), Albert Schweitzer (1952)--and to humanitarian organizations--International Committee of the Red Cross (1944 and 1963), U.N. High Commissioner for Refugees (1954 and 1981), Doctors Without Borders (1999).

In the past few decades, however, the Nobel Peace Prize has developed a certain political edge. The process might be said to have begun in 1962, when it was awarded to the 1954 chemistry laureate, the American Linus Pauling, whose anti-nuclear pronouncements were usually directed, with considerable heat, toward his own government. In some instances the committee has aimed its arrow at a proper target--Andrei Sakharov (1975), Lech Walesa (1983), the Dalai Lama (1989), Aung San Suu Kyi (1991)--but such lucky shots have grown increasingly rare.