The Italian government’s borrowing costs for two years soared from 0.94 percent to 2.42 percent Tuesday, as investors demanded greater compensation against the risk that the Italian government might repay them not with the rock-solid euro but with less valuable newly issued currency.

Meanwhile, Spanish two-year bond yields rose only slightly Tuesday — by 0.07 percentage points, not the 1.48 percentage points of Italian yields.

“The contagion has been really muted,” said Megan Greene, global chief economist at Manulife Asset Management. “I think investors are correctly looking at this as an Italy-specific risk for now.”

Bond investors seem pretty well persuaded that the issue here is not a broad a loss of confidence in Southern European nations’ ability to pay their debts. Since 2012, the European Central Bank has instilled confidence that it is willing to do “whatever it takes” — to use the memorable phrase of the E.C.B. president Mario Draghi — to preserve the euro.

Europe’s Dilemma

What is happening in Italy is more a political crisis than a financial one. Mr. Draghi’s tools are helpful only when a country’s elected leaders are trying to avoid crisis. They are of little use if a government truly wants to break away from the rest of Europe.

Other European countries, especially powerful Germany, will have little desire to subsidize what they view as fiscal profligacy in Italy. The push toward greater economic unity across Europe since the Greek crisis has included jointly guaranteeing the continent’s banks and the E.C.B.’s purchase of government bonds.

If there is conflict, both sides have reason to work things out. Germany and European institutions certainly don’t want a crackup of the eurozone. And within Italy, the economic consequences of peeling away from Europe — high inflation and lost savings in the near term and the long-term growth consequences from being a less appealing place for investment — are severe enough that there would be reason to strike a deal.