Mario Draghi is playing a high-stakes game of poker, and leaders from Europe’s biggest economies are trying to decide whether to call his bluff — or whether he’s bluffing at all.

Draghi, who became president of the European Central Bank less then two months ago, has placed a bet, declaring that the mighty ECB will not print money to arrest the debt crisis facing the continent. In a speech Tuesday, he warned that there will be no “external savior” for deeply indebted governments, urging them instead to put their financial affairs in order.

The leaders of Germany, France, Italy and Spain are at the table, each trying to decide how to respond. So are gigantic banks and other global investors. U.S. and British leaders are watching from the side, afraid of what might happen if things go awry.

The stakes on the table: the $16 trillion European economy.

No one knows for sure whether Draghi will hold to his tough line or fold. How open, in other words, could Draghi ultimately be to use the ECB’s power to keep the debt crisis from spiraling out of control if it means undermining the central bank’s political independence and risking inflation? What would it take for him to unleash the ECB and order massive purchases of bonds issued by Italy, Spain and other struggling governments to ensure they can continue to borrow money needed to avoid default?

Close to his vest

Since he became ECB chief, Draghi has been a master of ambiguity, sending conflicting signals — deliberately, many watchers of the ECB believe — about what he and his colleagues are willing to do to prevent Europe’s implosion.

Draghi, 64, headed Italy’s central bank before ascending to the ECB presidency on Nov. 1 as the crisis escalated — particularly in his home country. Italy’s borrowing costs were soaring as investors lost confidence in Rome’s ability to honor its obligations. A flood of data showed that the continent was headed toward recession, which would further aggravate the debt crisis.

Draghi, a dapper, MIT-trained economist with long experience in high-level economic diplomacy, has been willing to use many of the ECB’s tools to address the crisis. He cut the ECB’s main interest rate at his first two policy meetings, easing monetary policy to try to boost ailing European economies, over objections in at least one instance from some of his colleagues.

And he has offered the ECB’s backing to the continent’s banks, offering them unlimited loans in euros for the unprecedented length of three years at a time. He has also joined with top central bankers at the Federal Reserve and elsewhere in restarting a program to make dollars available to European banks that need them.

But those policies are treating the effects of the crisis — a slowing European economy and difficulty for banks seeking funds — and not addressing the more fundamental problems. Central to the crisis is deepening fear among ­global investors that Italy, Spain and other European governments will be unable to pay off their debts, ultimately leading to a break-up of the 17-nation euro zone.

The ECB could combat the loss of investors’ confidence by using its own ability to print money to buy troubled governments’ bonds. The central bank began buying billions of dollars of Italian and Spanish bonds this fall to help moderate a spike in their interest rates. Even this step, which was designed as a modest initiative to temporarily ease the pressure on bond markets, was criticized by some officials in Germany and elsewhere as overreaching by the ECB.

These critics see such programs as violating a founding principle of the common currency area: that the ECB would not create money — thus risking inflation — to prop up national governments.

In particular, Germany’s influential central bank, the Bundesbank — which is represented on the ECB policymaking committee — has a deep aversion to such a step, viewing it as a violation of the rules under which the ECB was established more than a decade ago.

Against that backdrop, Draghi has played a delicate game, hinting at but not promising more ECB bond purchases if European leaders commit to restraining future budget deficits.

On one hand, Draghi has sought to disabuse European leaders and financial markets of the idea that the ECB will use its ability to create money from thin air to finance government debt.

“What makes you think that the ECB becoming the lender of last resort for governments is what is needed to keep the euro area together?” Draghi asked Nov. 3 at his first news conference. “No, I do not think that this is really within the remit of the ECB.”

Four weeks later, he seemed to show greater openness to buying bonds, testifying before the European Parliament that “other actions might follow” a new accord on a more unified European approach to fiscal policy.

Draghi may be signaling that the ECB will only ramp up bond purchases, in effect buying time, if European leaders commit that euro-zone countries as a whole will get a handle on the government finances of member countries. The goal would be for these governments to subject their budgeting policies to greater control by centralized euro-zone agencies, easing the way for euro-zone governments as group to begin guaranteeing one another’s debts.

But that is a risky strategy.

“The optimistic view is he is playing a game of chicken with the markets, and that’s very dangerous,” said Rob Shapiro, chairman of Sonecon, a global economic consulting firm. “Markets could turn on a dime and decide the ECB will never step in, and then you have an all-out sovereign-debt crisis.”

Building relationships

Through it all, Draghi has maintained strong relationships with U.S. officials and many of the key parties in Europe. He and Treasury Secretary Timothy F. Geithner speak frequently and share a particular affinity; they know each well after both serving at senior levels of their respective finance agencies in the 1990s and then as top central bankers in the 2000s. Draghi’s relationship with his U.S. counterpart, Federal Reserve Chairman Ben S. Bernanke, is similarly warm, though they are in somewhat less frequent contact.

In his own country, Draghi is part of a technocratic elite that had long distanced itself from the scandal-ridden former prime minister, Silvio Berlusconi. The new Italian prime minister, Mario Monti, is from the same class of educated civil servants. He and Draghi appear to share a desire for change in Italy’s growth-choking regulatory and tax policies.

Draghi’s relationship with German leaders has been more fraught. Just a few months before his appointment, it appeared more likely that a German would take over the ECB presidency, though those hopes ended when Bundesbank President Axel Weber resigned at the start of the year, saying he disagreed with the ECB’s direction.

And while Draghi is respected by the German political elite, the German public tends to be skeptical of the man who hails from one of the very countries that is in financial trouble.

“Being an Italian, he has to establish his credentials with the Germans as being a tough, hard, money man,” said Desmond Lachman, a resident fellow at the American Enterprise Institute.

Back-door bonds

Draghi has, in effect, found ways to support government bonds through back channels, particularly with the support offered for banks. Banks can now post unlimited amounts of government-issued bonds as collateral in return for cash from the ECB. As result, the banks have an extra incentive to buy those bonds — or at least not sell their massive holdings.

“The only option open to Draghi has been to let the commercial banks buy government bonds, then accept those bonds as collateral for ECB funding,” said George Feiger, chief executive of Contango Capital. “But that’s the riskiest conceivable strategy because it means the banks are doubling down on government bonds, so even small losses would eviscerate their entire capital base.”

Draghi’s personal characteristics make him a good fit for the task ahead, said those who have watched him up close, even if there are no guarantees of success. Draghi is “a flexible and pragmatic administrator,” said Nathan Sheets, a former top international economist at the Federal Reserve who now heads international economics at Citigroup.

“By instinct, he is oriented toward providing financial support and addressing the situation with policy, but not in a way that risks tearing the ECB apart or pitting it directly against the German political system,” Sheets said.