Colin Powell was a rising star -- until he made the grave error of serving under George W. Bush: author

For years, it seemed as though the late Colin Powell's political star would never fall -- until, writes Slate's Fred Kaplan, he made the grave error of serving as Secretary of State under former President George W. Bush.

In writing up a summary of Powell's long career -- in which he served as a general, national security adviser, chairman of the Joint Chiefs of Staff, and secretary of state -- Kaplan argues that Powell's downward trajectory in the public eye began when he joined the Bush administration and found himself outmaneuvered at every turn by hawkish Vice President Dick Cheney and his allies.

"He lost almost every... battle," Kaplan writes of Powell's early days on the job. "In one of his first statements, Powell declared that he would resume President Bill Clinton's nuclear negotiations with North Korea—only to be told by Condoleezza Rice, Bush's national security adviser, that he would do no such thing. He had to eat his words."

The lowest point for Powell, writes Kaplan, came during his infamous presentation at the United Nations about Iraq's purported weapons of mass destruction stockpile.

"All the claims that Powell... believed -- all the evidence he recited to support the idea that Saddam Hussein possessed weapons of mass destruction -- turned out to be false as well," argues Kaplan. "In his excellent book, To Start a War, Robert Draper wrote that plenty of CIA analysts could have told Powell that the claims were false, or at least dubious—but that CIA Director George Tenet, eager to please Bush with the conclusions Bush wanted to hear, deliberately kept Powell from talking with them."

Powell would leave the Bush White House after the end of Bush's first term and would largely stay out of the public spotlight in the years to follow, although he did give a high-profile endorsement to former President Barack Obama in 2008.

Read Kaplan's whole essay here.