The war between Israel and Hamas is bad, but it could get much worse.

More so than any Arab-Israeli crisis since 1973, this conflict has the potential to expand and intensify, pulling in actors across the region and beyond. The nightmare scenario is that the current fight becomes a larger conflagration involving the Lebanese terrorist group Hezbollah, Iran and the U.S.

Preventing that escalation is Washington’s top priority. That won’t be easy, if recent events are any guide. The U.S. has powerful means of controlling the conflict, if it is willing to use them. But even in an optimistic scenario, the regional turbulence this war generates won’t abate anytime soon.