Other European leaders may press Spain for an answer before an October 18-19 summit. The country will also need to borrow more money in late October to pay off bonds that are coming due.
Analysts at Nomura think Spain will hold off asking for help at an upcoming European finance ministers' meeting Sept. 14. This could trigger worry in financial markets. If bond yields rise again, "this should eventually push Spain into a bailout before the end October because of market pressure," they wrote.
— What is holding Rajoy back?
Rajoy is aware of the political downside of asking for help. He said for months Spain wouldn't need a financial lifeline. Now, however, he says he has made no decision.
"The Spanish are really proud. People always fail to understand that," said Gayle Allard, an economics professor at Madrid's IE Business School. But she noted that Rajoy is caught between political dishonor and economic infamy that is already tarnishing his government's record. "The (bond market) battering early this summer was bad enough that (Rajoy) might want to rescue his reputation," she said.
Rajoy is also wary of his voters. A recent €65 billion ($82.59 billion) package of tax hikes and spending cuts triggered widespread public protests. He has committed to maintaining pensions at their current level — but that promise might be hard to keep if Europe demands sharp deficit cuts.
Rajoy was elected in a landslide in late 2011 and has an absolute majority in Parliament, and isn't required to hold elections until late 2015.
"He's losing support but it's something he can afford now during his first year in office," Antonio Moreno, an economist at the University of Navarra, said.
—What about Italy?
Italy is in a slightly better shape than Spain and can afford to wait a little longer before accepting the ECB's conditions. Italian Prime Minister Mario Monti praised Draghi's plan as an "important step forward" but said any decisions on Italy's potential request for aid were "premature."
Nonetheless the country is struggling to manage its huge debt load — 120 percent of its economy. Plus its hand may be forced if Spain does apply for assistance. Barcelona-based economist Edward Hugh says if Spain enters the bond-purchasing program, but Italy decides to pass on the ECB's offer, Rome's yields could surge amid investor nervousness. "That could force them in," he said.
Barry Hatton in Lisbon, David McHugh in Frankfurt and Al Clendenning and Harold Heckle in Madrid contributed to this article.
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