Afghanistan: There are two models for turning things around in what Democrats once called "the good war." One is the successful Bush surge used in Iraq. The other is the disastrous incrementalism applied in Vietnam.

CBS News reports that President Obama "has tentatively decided to send four combat brigades plus thousands more support troops" to Afghanistan. A "senior officer" told CBS the decision was "close" to the request made by the president's handpicked Afghanistan commander, Gen. Stanley McChrystal.

The White House denies a decision has been made, but the CBS report goes into great detail: Apparently, no new troops will arrive until early 2010, and the entire force won't be there until year-end . This means that a "surge" would not really be a surge at all in the Iraqi sense: It took President Bush just five months to add 30,000 troops in Iraq to employ a new counterinsurgency strategy.

So why would the president not want to employ a tested formula in Afghanistan? Are we on the verge of a repeat performance of the "McNamara syndrome"?

Robert McNamara, defense secretary for Presidents Kennedy and Johnson, was one of Ford Motor Co.'s "whiz kids" and one of "the best and the brightest" JFK surrounded himself with. His obsession with statistics worked pretty well at Harvard Business School and Ford. But his eggheaded arrogance proved calamitous when applied to the Vietnam War.

Though he had expert military men briefing him, McNamara appeared, as Marine Commandant Gen. M. Wallace Greene Jr. complained in 1964, "to think that he knew more about all the military aspects of the problems in Vietnam and the cures" than the professionals fighting the war.

Rather than rely on those veterans, Johnson gave McNamara "primary responsibility for managing the war in Vietnam," notes Marine Corps University historian Mark Moyar in his account of the Southeast Asia conflict, "Triumph Forsaken."

"Although Johnson's generals favored striking North Vietnam quickly and powerfully," Moyar wrote, the president chose "the prescriptions of his civilian advisers," headed by McNamara, "who advocated an academic approach that used small doses of force to convey America's resolve without provoking the enemy."

McNamara and the whiz kids thought North Vietnam would "reciprocate with self-limitations." Instead, "Hanoi's appetite and courage" intensified and "in November 1964, Hanoi began sending large North Vietnamese Army units to South Vietnam, with the intention of winning the war swiftly" -- a changed strategy the U.S. was fatefully slow in recognizing.

It may be that President Bush spent years acquiescing in a flawed Iraq War policy. But when the entire Washington establishment, both Democratic and Republican, pressured him in late 2006 and early 2007 to throw in the towel, he chose to double down and win.

The bipartisan Baker-Hamilton Iraq Study Group had recommended a phased withdrawal and direct negotiations on Iraq's future between the U.S. and the terrorist states of Iran and Syria. Bush instead turned command in Iraq over to the military's foremost expert on counterinsurgency warfare, Gen. David Petraeus, promptly giving him the extra forces needed for a new "clear and secure" strategy against urban insurgents.

Then-candidate Barack Obama's reaction to Bush's decision was a call for a phased redeployment of U.S. troops out of Iraq. He was wrong then, and Bush was right.

Will the president now learn from his mistake and adopt a Bush-style surge? Or will it be whiz-kid Vietnam incrementalism?