Secretary of State Colin Powell (search) is walking a thin line between boosting his boss for re-election and maintaining a traditional distance from the rough and tumble of election-year politics.

Probably rounding out his last months as a prominent public servant, Powell has declared he is obliged as secretary of state not to engage in "parochial debate."

At the same time, he stoutly defends President Bush's policies, including the one on which his contest with Democrat John Kerry (search) may turn — the war in Iraq.

The decision to overthrow Saddam Hussein (search) with massive Unator, voted for the war. But as a presidential candidate, he is challenging Bush's approach as go-it-alone unilateralism that cost the United States important European support.

He also accuses the president of an inclination to take pre-emptive action, even while saying he would not rule out taking such action himself in certain situations.

Powell has publicly disagreed with Kerry's characterization of Bush's approach. Is that politicking by the secretary of state? Or is it expounding on U.S. foreign policy, as secretaries of state do even in election years?

It could be a matter of perception. Still, Powell, on the advice of the White House, will skip the Republican National Convention, which no sitting secretary of state in recent memory has attended.

Henry A. Kissinger, having served as secretary of state for Republican Presidents Nixon and Ford, spoke at the 1980 GOP convention that nominated Ronald Reagan against Democratic incumbent Jimmy Carter.

Kissinger slashed at Carter, accusing his administration of "drift, confusion, retreat and weakness in our foreign policy." He also described Carter's approach to world problems as "diplomacy of incoherency." No matter that the platform Reagan ran on opposed arms control agreements with the Soviet Union that Kissinger had supported.

In 2000, Powell, a former chairman of the Joint Chiefs of Staff then widely rumored to be in line for a top job if Bush won, spoke at the GOP convention that nominated Bush.

He praised Bush as bridging racial divides. However, Powell, the nation's most prominent black Republican, spoke in support of affirmative action and how it might help "a few thousand black kids get an education."

Four years earlier, Powell spoke at the convention that nominated Bob Dole for president. There, too, Powell spoke in support of affirmative action, which is taboo to most Republicans. At the 1996 gathering, former Secretary of State James A. Baker also spoke, and blasted President Clinton's foreign policy as "Gullible's Travels."

State Department spokesman Adam Ereli said last week that "on White House instruction, Secretary Powell as well as others among the Cabinet, will not attend" the Republican convention, which opens Aug. 30 in New York City.

"This is in keeping with past practice," he said.

And so it is, so far as secretaries of state are concerned.

But being in Bush's Cabinet does not automatically disqualify officers from campaigning.

Commerce Secretary Donald Evans, who was Bush's campaign chairman in 2000, will attend the convention, spokesman Ron Bonjean said. Education Secretary Rod Paige is scheduled to speak at the convention. Paige, who is black, is expected to make the case that Bush's education agenda helps poor and minority children.

With the economy rivaling Iraq as the most decisive issue in the Bush-Kerry race, Treasury Secretary John Snow is campaigning for the president in states where the contest is close.