It’s often said that generals fight the last war.

 

That’s not always the case in the American experience.

 

In the past 40 years, the U.S. military has executed major military endeavors in Iran, Grenada, Libya, Panama, Kuwait, Iraq (twice), Somalia, Haiti, Serbia and Afghanistan. And that’s to say nothing of the operation this past spring where the U.S. military dispatched a legion of pirates.

 

That’s a lot of military intervention.

 

But the U.S. doesn’t fight the last war. It seems to fight the last war that went wrong: Vietnam.

 

President Obama will announce his vision for American operations in Afghanistan during a prime-time speech Tuesday night. Defense Secretary Robert Gates, Chairman of the Joint Chiefs of Staff Mike Mullen and Secretary of State Hillary Rodham Clinton are poised to testify to Congress this week about Mr. Obama’s Afghanistan outline. And Gen. Stanley McChrystal, the top commander in Afghanistan, is said to be close behind.

 

Republicans have hounded Mr. Obama for months about making a decision on the way forward in Afghanistan. Meantime, some of the most-liberal Democrats in Congress oppose the addition of any more forces. The president’s decision leaves them scratching their heads why the U.S. is increasing its commitment to Afghanistan when part of the reason some voters elected President Obama was to dial down American involvement in Iraq.

 

So as the week develops, expect lawmakers to draw exhaustive comparisons between Afghanistan and Vietnam. And both sides will invoke the specter of Vietnam as “code” to help advance their cause.

 

In other words, the “code” is that the U.S. “lost” in Vietnam. So if you “Vietnamize” Afghanistan, one can invoke fear that the U.S. might expect the same fate in Afghanistan if leaders don’t make the right decisions.

 

Former Rep. Duncan Hunter Sr. (R-CA) suggested to CBS’s Face the Nation in 2006 that mentioning “Vietnam” was a tactic from anti-war voices on the left.

 

“You've got some liberal Democrats who have died of old age waiting for the second Vietnam,” Hunter said of those who fretted about Iraq morphing into another Vietnam.

 

But the Vietnam fulcrum works two ways.

 

Those in favor of adding more troops in Afghanistan now cite Vietnam to bolster their position. They argue that if the U.S. doesn’t infuse Afghanistan with additional troops, America will become bogged down with no chance of clear victory. However, some believe the U.S. has no choice but to fight in Afghanistan.

 

“Unlike Vietnam, Afghanistan is a place from which America was attacked on 9/11/01,” said Sen. Joe Lieberman (I-CT) on FOX in late summer. “If we pull out or try a strategy that doesn't work, those who attacked us will regain the country. That is unthinkable.”

 

Meantime, anti-war lawmakers make the case that Afghanistan is “unwinnable” and ask why the U.S. should expend additional blood and treasure there.

 

“My fear is that we can get sucked into a quagmire like we did in Vietnam,” said Sen. Bernie Sanders (I-VT) on MSNBC in September. “We have already lost over 700 troops. We've spent $200 billion.”

 

This “Vietnamization” of wars isn’t new. Lawmakers wary of the Gulf War in 1990 and 1991 worried that the U.S. could be trapped in Iraq or Kuwait. The same thing happened in late 2002 and early 2003 as the U.S. prepared to again invade Iraq.

 

And reporters are always quick to find parallels between the conflict of the day and Vietnam.

 

In March 2002, the U.S. suffered its worst day of casualties in 30 years after a brutal firefight in Afghanistan. At the time, Gen Tommy Franks was the commander prosecuting the war in Afghanistan. And at the beginning of his press conference, Franks extended his condolences to the families of troops who were killed that day “here in Vietnam.”

 

An astute reporter picked up on Franks’ gaffe and asked him about it at the end of the new conference. The reporter wondered if there was something about the incident that reminded Franks of Vietnam. After all, Franks was wounded multiple times in Vietnam.

 

Franks said no. Vietnam “was a long time ago,” Franks said. The general even thanked the reporter for the correction.

 

But Franks’ subconscious slip-up reflected the elephant in the room. The U.S. military had a bad day on the battlefield. Chasing down the Taliban and al-Qaida in the crevices and mountains of Afghanistan was akin to searching for Charlie in the swamps and jungles of Vietnam. And public patience was wearing thin about Afghanistan. There was worry the war could become another Vietnam.

 

In late summer, Sen. Jim Webb (D-VA) told the NewsHour with Jim Lehrer that Afghanistan is “a totally different situation” than Vietnam. Senate Foreign Relations Committee Chairman John Kerry (D-MA), who won Three Purple Hearts and the Bronze Star in Vietnam, told a recent Congressional hearing that the U.S. is “obviously in a very different kind of war than” Vietnam in Afghanistan.

 

But the first Vietnam veteran elected to Congress, Rep. John Murtha (D-PA), isn’t so sure.

 

“When I was in Vietnam, we had 250,000 troops. Then we had 500,000. And it made no difference,” Murtha said. “There is no military solution to this.”

 

Vietnam is iconic in the American experience. Even for those who didn’t live through it. It’s present in films like Platoon and TV shows like M*A*S*H (which portrayed the Korean War, even though everyone knew it was about Vietnam). You hear the echoes of Vietnam in the ominous guitar chords from Jimi Hendrix’s “All Along the Watchtower.” Thousands of people flooded Max Yasgur’s pasture in upstate New York this past August to mark the 30th anniversary of Woodstock. And a few years ago, Rep. Charlie Rangel (D-NY) authored a bill to re-institute a draft.

 

We’re sure to hear a lot about Vietnam in the next week on Capitol Hill. That’s because the U.S. is essentially fighting two wars. One is in Afghanistan. The other is Vietnam. In the American psyche.

 

-               Chad Pergram covers Congress for FOX News. He’s won an Edward R. Murrow Award and the Joan Barone Award for his reporting on Capitol Hill.

 

-               The Speaker’s Lobby refers to a long, ornate corridor that runs behind the dais in the House chamber. Lawmakers, aides and journalists often confer there during votes.