The Italian government’s populist spending plans — a proposal is due to Brussels on Monday — have bond investors worried about the potential for another debt crisis.CreditCreditNadia Shira Cohen for The New York Times

By Jack Ewing and Jason Horowitz

History suggests that the world is about due for another financial crisis. One of the places it might start, according to a growing number of indicators, is Italy.

Many of the ingredients are there. A pile of questionable debt. Weak banks. An erratic government. And a sizable economy able to inflict collateral damage outside Italian borders.

Bond investors, always good for a coldblooded appraisal of a country’s solvency, have been sounding the alarm. The Rome government’s populist spending plans, widely regarded in financial circles as reckless, have caused market interest rates on Italian debt to spike, threatening to create a so-called doom loop that would ripple through the struggling economy.

The proposed budget has exposed the seams in Italy’s governing coalition, where one party favors small-business-friendly tax cuts and the other enormously expensive welfare programs. More broadly, it has divided the populist government, which has vowed to press ahead with a budget it views as a political imperative, and the Italian financial establishment, which fears what the spending will do to the country’s economy and its credibility and relationship with Europe.

You don’t have to be Italian to be worried about the repercussions.

Financial crises tend to arrive every decade or so, and Italy is near the top of a list of flash points that could touch off the next one, alongside Turkey’s economic and political turmoil, President Trump’s trade war, Britain’s exit from the European Union and a broad slowdown in global growth.

But in contrast to the financial crisis that began in 2008, central banks may not be able to come to the rescue this time, said Richard Portes, a professor of economics at London Business School. They used up much of their crisis fighting tools coping with the last meltdown.

“It would be very difficult for Mario Draghi to think of another way to get out of the mess,” Mr. Portes said, referring to the president of the European Central Bank.

That is why investors are so worried about Italy. The eurozone is still recovering from a debt crisis that began in Greece in 2010. Italy, the currency bloc’s third-largest economy, accounts for 11 percent of the European Union’s gross domestic product — 10 times as much as Greece — and has the potential to create far more damage.

Many of the country’s problems are longstanding, such as the unusually high number of problem loans on its banks’ balance sheets and chronically slow growth. Italy’s economy has still not made up the ground it lost after the 2008 financial crisis. The new element is Italy’s populist government, which to the horror of European Union officials and bond markets is pledging money it doesn’t have to fulfill campaign promises.

Unlike previous Italian governments that bristled at, but ultimately complied with, demands from the European Union, Italy’s populists have made their careers running against Brussels.

They are pursuing a brazenly confrontational course with the European Commission, never mind the market reaction or the consequences for Italian savers, who are among the biggest holders of government bonds.

“The enemies of Europe are those barricaded in the bunker of Brussels,” Matteo Salvini, the leader of the anti-immigrant League and the country’s most powerful politician, said this week in a news conference. He has repeatedly called Jean-Claude Juncker, the European Commission’s president, and Pierre Moscovici, its economics commissioner, the villains who “have ruined Europe and our country” through austerity measures.

Under eurozone rules, Italy must submit its budget for European Commission scrutiny by Monday. The proposed spending plan calls for a deficit equal to 2.4 percent of gross domestic product, a figure considered way too high for a country whose total government debt equals 131 percent of G.D.P., more than double the eurozone limit.

The previous, center-left government had proposed a budget with a 0.8 percent deficit, which would have allowed Italy to continue chipping away at its total debt.

A significant portion of the new budget would go toward a broad welfare program, a key campaign promise of the anti-establishment Five Star Movement to its young, unemployed and frustrated base, many in Italy’s depressed south.

“In a decisive manner, with this measure, with this budget, we will have abolished poverty,” said Luigi Di Maio, the political leader of the Five Star Movement and Italy’s economic development minister, in a television interview last month.

A negative report on the proposed budget by Fitch Ratings on Wednesday has injected extra anxiety into the budget negotiations. In its report, Fitch cited the “disorderly buildup” to the budget presentation and the disagreement between Five Star and League on fiscal priorities, the lack of detail on tax proposals and the gulf between the “high cost of implementing core policy pledges and the objective to reduce public debt.”

In addition, the hostile tone that the Italians have taken with the European Union, the very thing that helped put them in power, “indicates that the government sees political opportunities in attacking the E.U.’s fiscal rules, especially in the run-up to European parliamentary elections next May,” the report said.

Fitch has signaled it could downgrade its rating of Italy’s debt, a step that if matched by other ratings agencies would further raise the government’s cost to borrow.

The government has cut some expenditures, but in categories that further provoke Brussels. For example, Rome has suspended plans to acquire a new missile defense system at a time when Europe is trying to appease Mr. Trump by spending more on NATO.