WASHINGTON (AP) — Reiterating a threat he first issued in the summer of 2011, President Barack Obama on Monday warned Republicans that older Americans might not get their Social Security checks and veterans won't get timely benefits if Congress fails to increase the government's borrowing authority.

Republicans are insisting on spending cuts in exchange for raising the current $16.4 trillion debt ceiling. Obama vowed Monday not to use the debt ceiling to negotiate deficit reduction. "We are not a deadbeat nation," he declared, creating an inevitable showdown with congressional Republicans.

The government could run out of cash to pay all its bills in full as early as Feb. 15, according to one authoritative estimate. That means Washington could once again plunge into political brinkmanship like it did in 2011 when Congress ultimately raised the debt ceiling, but only after Obama agreed to broad spending cuts.

On Monday, Obama said Congress should act. "The full faith and credit of the United States of America is not a bargaining chip," he said.

"Republicans in Congress have two choices here," Obama said. "They can act responsibly, and pay America's bills, or they can act irresponsibly and put America through another economic crisis. But they will not collect a ransom in exchange for not crashing the American economy."

Without an agreement, every option facing his administration would be unprecedented.

It would require a degree of financial creativity that could test the law, perhaps even the Constitution.

It could shortchange Social Security recipients and other people, including veterans and the poor, who rely on government programs.

It could force the Treasury to contemplate selling government assets, a step considered but rejected in 2011. In short, the Treasury would have to create its own form of triage, creating a priority list of its most crucial obligations, from interest payments to debtors to benefits to vulnerable Americans.

"It may be that somewhere down the line someone will challenge what the administration did in that moment, but in the moment, who's going to stop them?" asked Douglas Holtz-Eakin, a former director of the Congressional Budget Office. "I pray we never have to find out how imaginative they are."

In such a debt crisis, the president would have to decide what laws he wants to break. Does he breach the borrowing limit without a congressional OK? Does he ignore spending commitments required by law?

In a letter to Obama on Friday, Senate Democratic leaders urged him to consider taking any "lawful steps that ensure that America does not break its promises and trigger a global economic crisis — without congressional approval, if necessary."

The White House has resisted that path. It has rejected recommendations that it invoke a provision in the 14th Amendment to the Constitution that states that "the validity of the public debt of the United States ... shall not be questioned."

"There are no magic tricks here," Obama said Monday. "There are no loopholes. There are no, you know, easy outs."

So what's left if Congress does not act in time?

Technically, the government hit the debt ceiling at the end of December. Since then, Treasury Secretary Timothy Geithner has halted full payments into the retirement and disability fund for government workers and to the health benefits fund of Postal Service retirees.

The Treasury can stop payments to a special fund that purchases or sells foreign currencies to stabilize world financial markets.

Past administrations have taken such steps to buy time awaiting a debt ceiling increase. That happened under Presidents Bill Clinton and President George W. Bush. The government restored those funds after Congress raised the debt ceiling.

Those measures and others could keep the government solvent, perhaps as far as early March, according to an analysis by the Bipartisan Policy Center.

There are other extreme possibilities as well.

The federal government could sell some of its assets, from its gold stockpile to its student loan portfolio.

"All these things are in principle marketable, and in a crisis you'd get huge discounts on them," said Holtz-Eakin, now head of the American Action Forum, a conservative public policy institute. "They wouldn't be good ordinary business, but you would be in extraordinary times."

According to a treasury inspector general report last year, department officials in 2011 considered and rejected the idea, concluding that gold sales would destabilize the international financial system, that selling off the student loan portfolio was not feasible and that such "fire sales" would buy only limited time.

An idea pushed by some liberals would take advantage of a legal loophole meant for coin collectors and have the Treasury mint platinum coins that could be deposited at the Federal Reserve and used to pay the nation's bills. But the Treasury issued a statement Saturday putting the idea to rest, saying neither the department nor the Federal Reserve believes the law "can or should be used to facilitate the production of platinum coins for the purpose of avoiding an increase in the debt limit."

Once all efforts are exhausted, then the government would be in uncharted territory.

At that point, the government would continue to get tax revenue, but hardly enough to keep up with the bills. According to the Bipartisan Policy Center, the federal government between Feb. 15 and March 15 will get $277 billion in revenue and face $452 billion in obligations.

The Treasury would have to decide whether to pay some obligations and not others or to simply pay for one day's bills as it tax revenue rolls in, exponentially delaying payments the longer the debt ceiling is not raised. Under virtually every scenario contemplated, payment of interest on the debt takes precedence to put off a calamitous default.

"I happen to think the triage would be chosen to create the maximum amount of political pressure to break the impasse right away, which would be withholding Social Security checks," said Philip Wallach, a fellow at the Brookings Institution.