When President Bush last went to Congress for funding for the wars in Iraq and Afghanistan, he raised the specter of US troops going without the reinforcements, equipment, training, fuel and all the other things they need to stay alive over there if Congress didn’t cut him a fat check with “no strings attached.” The newly elected Democrats caved, citing a need to fund the troops, and sent him $124 billion.

The past few weeks on Capitol Hill have been dominated by Iraq, as the GOP has continued to stand with the President and Democrats have been unable to muster the votes to force his hand. Soon, Bush will be asking for more funding–reportedly as much as $200 billion. When he does, he’ll again argue that the timely and “clean” passage of the spending bill is essential to keeping the troops equipped. But that’s not true. Thanks to the Feed and Forage Act, an obscure nineteenth-century statute, Bush could legally continue to prosecute the war without funding from Congress.

Passed in 1861, the law provided a way for Abraham Lincoln to assure funding for the Civil War. Since then, it has been used to secure funding for other wars. On Sept. 21, 2001, the Pentagon said in a press release, “Invoking the Feed and Forage Act…will ensure the Department of Defense can fully support units of the U.S. armed forces involved in military operations and activities resulting from the terrorist attacks on the World Trade Center, the Pentagon and the aircraft crash in Pennsylvania.”

The Feed and Forage Act doesn’t outright appropriate funds to the military, but allows it to “obligate” money–in other words, it allows the military to fight a war on credit, leaving the companies it does business with to rely on Congress to pick up the tab.

The Pentagon could acquire fuel, weapons, Hummers, bombs, food and any other supplies needed for the war effort with promises to pay suppliers the bills once Congress appropriates the money. No other federal agency or department has such authority–all others must have the cash in the bank. Defense industry vendors have historically been willing to take this gamble because their close relationship with Congress nearly always assures that the money will eventually be there. Economic competitiveness almost dictates that the companies participate. Besides, the obligations could be considered legally binding, and it’s inconceivable that Congress would never again fund the Defense Department. And when it does, these companies would be waiting in line.

I called the Pentagon to see if the act was on its radar at this point for Iraq. “It is an option,” said Lieut. Col. Brian Maka, a Defense Department spokesman, who was immediately familiar with the provision. He wouldn’t say whether the Pentagon would invoke it if need be, saying that such a decision would be made higher up.

If Congress refuses the Administration’s funding request and the President does invoke the Feed and Forage Act, it could set up a constitutional showdown. After all, the purpose of denying funds would be to force an end to the war. If that didn’t bring it to an end, Congress would be out of ammunition. House Speaker Nancy Pelosi’s office said Bush had better not try the constitutional runaround.

“Although Feed and Forage could give the President the ability to continue a military action for which Congress had not provided funds,” said an aide to Pelosi in an e-mail, “the Speaker believes that no President would act on so grave a matter in a manner inconsistent with the position of the Congress.”

If Bush did make use of the act, he’d have plenty of modern precedent to point to. The Clinton Administration invoked the act in 1994 to secure $126.3 million in military spending for operations in Haiti, according to a 1995 House report. In 1968, 1969 and 1972 the Defense Department invoked the act to fund the Vietnam War and other military operations in Southeast Asia, a 1995 Congressional Research Report says.

The use of the act during the Vietnam War may have the closest parallels to today. In both situations, Congress was attempting to force a President to end a war. “In 1973, Secretary of Defense Elliot Richardson threatened to use the Feed and Forage Act to continue bombing in Cambodia if Congress denied the Pentagon’s request for additional authority to transfer funds from one appropriation account to another,” reads the CRS report.

As in Vietnam, the threat of Bush’s invoking the act may be more powerful than its use. Bush could threaten to sidestep the will of Congress by employing the act. On the other hand, it could instead be a useful weapon for Democrats, who could note that Bush has legal means by which he can secure funding to meet the needs of troops even if Congress refuses more funding.

Former Defense Secretary Donald Rumsfeld, who invoked the act in 2001, isn’t the only administration official who knows how to fill out the Feed and Forage Act paperwork. The CRS report notes that in 1991, then-Defense Secretary Dick Cheney invoked the act to secure $1.6 billion in funding for the first Gulf War.