WASHINGTON — The fate of the global economy, European unity — and the 401(k) savings of ordinary Americans — all hang in the balance as Europe's leaders meet over the weekend to try to resolve a burgeoning debt crisis that threatens to spread globally.

The leaders are expected to decide at their European Union summit by next Wednesday whether and how to expand the controversial bailout fund they created earlier this year. They also must decide how to add extra cash to their faltering banks — in need of somewhere between $100 billion and $300 billion — in order to prevent collapses or runs by nervous depositors.

And they must decide whether Greece, the region's basket case that sparked the crisis, gets more rescue support and how much.

That's a pretty full plate. So full that leaders of France and Germany, the preeminent powers of the 27-member European Union, will continue meeting into next week rather than finishing their EU summit as planned on Sunday.

Technically, EU leaders have pledged to reach some resolution before leaders of the 20 most advanced economies — the G-20 — meet in Cannes, France, on Nov. 3-4. But investors across the globe are increasingly restless, and if EU leaders don't make visible progress soon, financial markets across the globe could spiral down as soon as Monday.

There's much more at stake in Europe than just the debt woes of a few countries. Six decades of work to integrate European economies, which collectively include 500 million consumers and economic activity in excess of $17 trillion — more than the USA, could unravel if leaders fail to find a solution.

"You've got a short-term problem, which is Greece ... and a longer-term problem where there are some serious structural and design flaws in the European Union," said Nariman Behravesh, chief economist for forecaster IHS Global Insight.

For more than a decade, Europe has had a common currency, the euro, and monetary policy set by a single entity, the European Central Bank. But the 27 member nations each have retained sovereign responsibility for taxation and spending, and many have amassed huge debts. It's as if the United States did not having a national Treasury Department and instead all 50 states had their own.

"It doesn't work. A unified currency without a political union, without a fiscal union — a federal system — just isn't going to fly," said Behravesh.

But adopting a common fiscal system would require countries with millennia of history to cede their sovereignty to some higher EU bureaucracy. Proud citizens of each nation likely would object, which means the politics of democratic Europe may preclude the EU from taking the structural economic reforms it needs to survive.

"We all know what to do, but we don't know how to get re-elected once we have done it," Jean-Claude Juncker, Luxembourg's prime minister, recently acknowledged.

Yet if Europeans fail to build a new economic order, an EU collapse would have severe economic consequences everywhere.

The 2008 U.S. financial crisis drove home how interconnected the global financial markets have become. When U.S. investment bank Lehman Brothers went bankrupt, a wave of panic swept global financial markets and credit froze across the planet.

Much like Americans angry about bank bailouts, Europeans aren't happy about having to bail out indebted nations such as Greece or Portugal. Most experts now think a structured default by Greece on its government bonds is inevitable.