For years, Israeli officials have worried about the threat of Hamas in the Gaza Strip. Still, they viewed a full ground invasion of Gaza to be too dangerous and costly to try. Many Israeli soldiers would die. The widespread killing of Palestinian civilians would damage Israel’s global reputation. The invasion might fail to dismantle Hamas.

Last weekend’s attacks by Hamas — killing more than 1,300 people, mostly civilians — have changed this calculation. Israel’s leaders and many of its citizens seem to have decided they now have no choice but to invade, and the military has ordered more than one million people to evacuate northern Gaza. Israel’s goals are to prevent Hamas from being able to conduct more attacks and to reestablish the country’s military credibility.

But the same challenges that kept Israel from invading Gaza before have not gone away. The war, as a result, has the potential to become another case study in the strategic difficulties of urban warfare, as the U.S. experienced in Falluja, Iraq, nearly two decades ago, Israel did in Lebanon during the 1980s and Russia has in Ukraine.

“It’s one of the most complicated fighting scenarios that you can have,” Alex Plitsas of the Atlantic Council told us. “It makes for bloody, awful conflict.”

In today’s newsletter, we preview the invasion that appears to be coming, focusing on two questions: What is Israel trying to accomplish? And what is Hamas’s strategy now?

Benjamin Netanyahu, Israel’s leader, has vowed to “crush and destroy” Hamas. But many analysts expect that the group will continue to exist, in some form, for the foreseeable future. What, then, would qualify as a success for Israel?

It would involve a Hamas that was so weak it could no longer govern Gaza, could no longer fire missiles into Israel and could no longer launch terrorist attacks that look anything like last weekend’s. To accomplish that, Israel is planning an invasion larger and longer than its previous campaigns into Gaza since Israel ended its occupation there in 2005.

Israel has mobilized 360,000 troops — more than 3 percent of its population — and cut off power, fuel and water to Gaza. That lack of resources has created dire problems for Gaza residents — and will also make it harder for Hamas to operate. In the meantime, Israel will try to kill or arrest Hamas fighters, destroy its supply of major weapons like missiles and close the tunnels where the group hides.

But Gaza’s densely populated streets will make the mission extremely difficult. Hamas fighters will be able to hide in alleys and buildings and will be difficult to distinguish from civilians. Civilian deaths, in turn, may damage Israel’s international support. Hamas’s leaders, as Tahani Mustafa, an analyst at the International Crisis Group, told us, “were definitely trying to draw Israel into a conflict.”

Thomas Friedman, the Times columnist, puts it this way:

What Israel’s worst enemies — Hamas and Iran — want is for Israel to invade Gaza and get enmeshed in a strategic overreach there that would make America’s entanglement in Falluja look like a children’s birthday party. We are talking house-to-house fighting that would undermine whatever sympathy Israel has garnered on the world stage, deflect world attention from the murderous regime in Tehran and force Israel to stretch its forces to permanently occupy Gaza and the West Bank.

The Israelis do have advantages, though. “They probably have detailed computer images of every major building in Gaza, and they can use robots and drones to scout those buildings, find the Hamas defenders and kill them,” David Ignatius of The Washington Post noted. “Many of the terrorists who kidnapped Israeli hostages were recorded on video — and it’s a safe bet that every one of them will be a target for Israeli revenge.”

Some experts believe that Hamas’s weekend attacks were more successful and deadlier than even Hamas’s leaders expected. Either way, Hamas almost certainly understood that the attacks would provoke a large Israeli response, and have prepared for it.

In the past, urban warfare has helped insurgent groups beat back stronger militaries. In the first battle of Falluja, in 2004, Iraqi militants were able to hold onto the city by fighting from a maze of buildings.

Hamas militants will probably use a similar approach in Gaza. They will hide in booby-trapped homes and tunnels, ready to lob grenades at Israeli troops. They will also likely dress as civilians, as they have in the past.

“It’s almost inevitable that Israeli strikes on Hamas targets will hit or wound civilians,” our colleague Steven Erlanger, who has covered the Middle East for years, said on “The Daily” this week. “And it’s partly because Hamas deliberately lives among them and hides its munitions among them and in mosques and in hospitals. I’ve seen these things for myself. And I don’t expect them to be any different this time.”

Finally, Hamas has the grim tactical advantage of holding at least 150 hostages. Israeli officials need to worry about the killing of these hostages with each attack. Hamas has also threatened to execute a hostage each time an Israeli airstrike hits Gazans in their homes.

Among the few confident predictions experts make are that the coming invasion will be brutal, and will include major surprises.

“That a major operation is coming is hardly in doubt,” The Times explains, in a preview of the likely ground invasion. “But there are tactical arguments over how any operation should start, whether it will begin massively or with raiding parties, and how best to coordinate Israel’s overwhelming strength in land, sea and especially air power.”

  • Representative Steve Scalise withdrew his bid to become House speaker after too many Republicans opposed him, leaving the chamber in chaos.

  • Jim Jordan, who finished second to Scalise in the nomination vote, and Patrick McHenry, the interim speaker, are possible alternate candidates.

  • Federal prosecutors filed a new charge against Senator Robert Menendez, a New Jersey Democrat, accusing him of acting as a foreign agent for Egypt.

Only the international community can stop another devastating Israeli assault on Gaza, Fadi Abu Shammalah writes.

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Modern Love: They have the same name.

Lives Lived: Rudolph Isley sang harmony and helped write hits like “Shout” as a member of the Isley Brothers, then left the mainstream music industry to become a minister. He died at 84.

M.L.B.: The Philadelphia Phillies beat the Atlanta Braves, 3-1, to advance to a second straight N.L.C.S.

A Denver swoon: The Broncos dropped to 1-5 with a loss in Kansas City last night, another sign that the Sean Payton era in Denver is already a disaster.

Golf: Lexi Thompson is playing in a P.G.A. Tour event this weekend — just the seventh female golfer to play against men in such a tournament. She is close to the cut line after 16 holes of play yesterday.

Sisterhood: Judy Chicago’s 1979 installation “The Dinner Party” is a landmark work of feminist art. Yet she had never had her own survey in New York — until now. “Herstory,” which spans four floors of the New Museum, covers six decades of Chicago’s work, along with pieces from artists and thinkers including Hilma af Klint, Zora Neale Hurston, Virginia Woolf and Frida Kahlo.