This is pretty depressing if you think of the heroic battle fought by US Marines in Fallujah in 2004 - the biggest urban battle fought by the US military since Tet. Al-Qaeda virtually took over the city two days ago when the Iraqi military was pulled out as a sop to Sunni lawmakers who thought they were being oppressed. AQ moved in and now, the military is going back, trying to wrest control of the city from al-Qaeda fighters.

A rejuvenated al-Qaeda-affiliated force asserted control over the western Iraqi city of Fallujah on Friday, raising its flag over government buildings and declaring an Islamic state in one of the most crucial areas that U.S. troops fought to pacify before withdrawing from Iraq two years ago.

The capture of Fallujah came amid an explosion of violence across the western desert province of Anbar in which local tribes, Iraqi security forces and al-Qaeda-affiliated militants have been fighting one another for days in a confusingly chaotic three-way war.

Elsewhere in the province, local tribal militias claimed they were gaining ground against the al-Qaeda militants who surged into urban areas from their desert strongholds this week after clashes erupted between local residents and the Iraqi security forces.

In Fallujah, where Marines fought the bloodiest battle of the Iraq war in 2004, the militants appeared to have the upper hand, underscoring the extent to which the Iraqi security forces have struggled to sustain the gains made by U.S. troops before they withdrew in December 2011.

The upheaval also affirmed the soaring capabilities of the Islamic State of Iraq and Syria (ISIS), the rebranded version of the al-Qaeda in Iraq organization that was formed a decade ago to confront U.S. troops and expanded into Syria last year while escalating its activities in Iraq. Roughly a third of the 4,486 U.S. troops killed in Iraq died in Anbar trying to defeat al-Qaeda in Iraq, nearly 100 of them in the November 2004 battle for control of Fallujah, the site of America's bloodiest confrontation since the Vietnam War.

Events Friday suggested the fight may have been in vain.

For those Americans who fought in Fallujah, there are varying perspectives on the current troubles:

"It was all for naught," said Ross Ducati, a former Marine who fought in the second battle for the city and has since become an outspoken critic of U.S. intervention in Iraq. "Americans fought and died there -- my friends died there -- for the purposes of regime change and furthering business interests friendly to the Bush administration... [Now] Iraqis will die there to further the interests of [Prime Minister Nouri] al-Maliki's government."

But other Marines don't share that view, seeing the latest confrontation with al Qaeda as part of an ongoing struggle for freedom in Iraq and across the region.

"We can't sustain fighting from 3,000 miles away forever," said Malkemus. "At some point we had to turn things over to the Iraqis. Unfortunately, the Iraqi Army is struggling and needs to engage with the terrorists again in Fallujah.

"American men and women who fought and died can never be forsaken, and we don't forsake them by keeping up the fight," he said.

The security situation in Iraq has deteriorated in the past year. According to the U.N., 7,818 people were killed in 2013, the highest number in years.

Much of the recent sectarian violence has taken place in Anbar province, where Fallujah is located. Prime Minister Maliki's Shiite-controlled government has tried to contain the violence in the province, a majority Sunni region.

Against the backdrop of al Qaeda backed militias launching attacks on police statements and military bases, the government has also cracked down on peaceful Sunni protests and sit-ins and dismantled Sunni militias, including those unaffiliated with al Qaeda.

The president's failure to sign a new status of forces agreement with the Maliki government led to our early withdrawal from Iraq. Many analysts believe Obama gave up on the negotiations too early - as he appears to be doing in Afghanistan with his inability to come to an agreement with President Karzai on future American troop deployments there.

It may very well be that President Obama had no alternative. As it stands now, his decision appears to have been reckless and ill-considered. We wouldn't have remained another 5 years - but even two years may have made a difference in today's fighting.

We'll never know.