by Emily Schwartz Greco and William A. Collins

How can the United States afford to keep proving that it's bad at bringing peace to conflict-ridden Middle Eastern countries?

We're at it again.

After months of commendable restraint, President Barack Obama has decided to send weapons to the besieged Syrian rebels. This is either a bid to overthrow a friend of Iran or a ploy to capture Syria's oil. Or both.

Sound familiar? It should.

Back in the 1980s, Uncle Sam armed Osama bin Laden and other besieged rebels in Afghanistan. Apparently, our leaders think that bid to drive out the Russians in a region with key energy interests was a big success. And, they want to try it again.

The tipping point this time involves poison gas -- Obama says he's got evidence that Syrian leader Bashar al-Assad used it on his own people.

Perhaps.

Regardless of the rationale, we must first reckon with the horrific results of our other wars in the Middle East.

Consider the fate of Fallujah, a former target of U.S. military attention in Iraq. After the city was leveled, its birth-defect and miscarriage rates skyrocketed, the Environmental Contamination and Toxicology Bulletin found.

Experts estimate that some 1 million Iraqis died from combat, malnutrition, and pollution during the course of the Gulf and Iraq wars. Many millions more were driven from their homes. And an alarming percentage of the people who remain there are getting cancer.

The cause of this huge toll on Iraqi lives and well-being is no great mystery. War is a dirty business.

Those millions of exploded munitions we detonated in Iraq contained lead and mercury. Hundreds of thousands more (the Pentagon won't say how many) released depleted uranium, a toxin now dispersed in fine dust all over Iraq and Afghanistan. Others featured white phosphorus.

President George W. Bush's Iraq War didn't begin the U.S. assault on Iraq's public health. His father, President George H. W. Bush, oversaw the bombing of Iraq's water purification plants during the 1991 Gulf War. This brutal tactic has caused countless deaths over the past two decades.

The Iraqi people weren't the only ones poisoned. Our men and women in uniform have suffered too. Around 200,000 Gulf War veterans suffer from medically unexplained but chronic symptoms known as Gulf War syndrome. They include fatigue, headaches, joint pain, indigestion, insomnia, dizziness, respiratory disorders, and memory problems.

A new wave of illness is gripping Afghanistan and Iraq War vets. In many cases, these ailments are tied to the military's environmentally irresponsible "burn pits."

The Veterans Administration notes that those pits routinely torched "chemicals, paint, medical and human waste, metal/aluminum cans, munitions and other unexploded ordnance, petroleum and lubricant products, plastics and Styrofoam, rubber, wood, and discarded food." Plus some other stuff you can't legally incinerate in your fireplace.

Getting to the bottom of the burn pit problem will take time and money. Representative Tim Bishop, a New York Democrat, recently introduced the Helping Veterans Exposed to Toxic Chemicals Act. His bill would get the much-needed research done to find out whether burn pits harmed the health of our men and women in uniform.

Until the research is done, vets can file disability claims the VA will decide "on a case-by-case basis."

There are many costs of war. In monetary terms, Americans are likely to pay more than $1 trillion just on caring for the many veterans of the Afghanistan War, according to Nobel-Prize winning economist Joseph Stiglitz and Harvard University professor Linda Bilmes.

Before Washington really ramps up the U.S. role in Syria, let's contemplate the price tag for the quagmires in Iraq and Afghanistan. It could reach $6 trillion, according to Bilmes -- who served as the Commerce Department's CFO during the Clinton administration.

Just as it's now impossible to make a rational argument that our armed forces can bring peace to Middle East conflicts, it's mind-boggling to argue that we can afford to try this again.

Back to that aid Obama pledged weeks ago. Apparently, it hasn't shown up in Syria yet.

Reuters reports that those funds have "been temporarily frozen" after the House and Senate intelligence committees expressed doubts about how this all-too-familiar plan would keep weapons away from militants aligned with al-Qaeda.

Sometimes our do-nothing Congress does something right by doing what it does best.