Israeli Prime Minister Benjamin Netanyahu speaks before Congress on Wednesday in hopes of bolstering US support for continuing Israel's offensives against Hamas and other adversaries. But boycotts of his appearance by some Democratic lawmakers and expected protests outside are highlighting how his hard-line government's conduct of the devastating war in Gaza is opening fissures in longstanding American support for his country.

Netanyahu is assured a warm welcome from Republican lawmakers who arranged his speech in the House chamber, an appearance making him the first foreign leader to address a joint meeting of Congress four times, surpassing Winston Churchill.

Many Democrats and political independent Bernie Sanders plan to boycott Netanyahu's appearance. But the most notables absence will be behind him: Vice President Kamala Harris, who serves as president of the Senate and traditionally would sit behind whatever dignitary is speaking, says a long-scheduled trip will keep her away Wednesday. And the next Democrat in line, Sen. Patty Murray of Washington, is declining to attend.

Republicans targeted the absence of Harris, the new Democratic front-runner for the presidency, as a sign of disloyalty to an ally. However, former President Donald Trump's running mate, JD Vance, said campaigning would also make him a no-show for the Israeli leader's speech.

And outside the Capitol, demonstrators angry over the deaths of nearly 40,000 Palestinians, or over Netanyahu's inability to free Israeli and American hostages taken by Hamas and other militants in the first hours of the Israel-Hamas war, are promising massive protests.

In anticipation, House Speaker Mike Johnson warned of a “zero-tolerance policy” for any signs of disturbances in the Capitol building. “It is our tradition to acknowledge every guest speaker's right to free expression even if we disagree with their viewpoint,” the Louisiana Republican wrote to members Tuesday.

Johnson arranged the address, an honour that marks both the two countries' historically warm bonds and the political weight that support for Israel has long carried in US politics. But the attention for the visit has been diminished some by American political turmoil of recent weeks, including the assassination attempt against Trump and President Joe Biden's decision not to seek another term.

Netanyahu hopes to project the image of a tough, respected statesman for an increasingly critical domestic audience back home in Israel. That may be difficult given the wide division among Americans over Netanyahu's conduct of the war.

Many Democrats who support Israel but have been critical of Netanyahu see the address as a Republican effort to cast itself as the party most loyal to Israel and to provide the prime minister with a much-needed political reprieve.

"I don't know all the motivations for Speaker Johnson initiating the invitation but clearly he wanted to throw a political lifeline to Netanyahu whose popularity is very low in Israel right now,” Sen. Chris Van Hollen, among the dozens of Democrats set to boycott, said Tuesday.

Still, many Democrats plan to attend the address despite their criticism of Netanyahu, including Senate Majority Leader Chuck Schumer, who called for new elections in Israel in a March floor speech. Schumer, of New York, said then that Netanyahu has “lost his way” and is an obstacle to peace in the region amid the humanitarian crisis in Gaza.

Netanyahu also is to meet with Biden and Harris on Thursday, and Trump at Mar-a-Lago on Friday.

The United States is Israel's most important ally, arms supplier and source of military aid as Israel battles to break Hamas since the group attacked Israel on Oct. 7.

Netanyahu's visit is his first abroad since the war started, and comes under the shadow of arrest warrants sought against him by the International Criminal Court over alleged Israel war crimes against Palestinians. The United States does not recognize the ICC.

The Biden administration says it wants to see Netanyahu focus during his visit on helping it complete a deal for a cease-fire and hostage-release in the nine-month war. Growing numbers of Israelis accuse Netanyahu of prolonging the war in order to avoid a likely fall from power whenever the conflict ends.

Netanyahu says his aims for the US visit are to press for freeing hostages held by Hamas and other militants in Gaza, to build support for continuing Israel's battle against the group, and to argue for continuing to confront Hezbollah in Lebanon and other Iranian-allied groups in the region. The US, France and others are seeking to calm border fighting between Hezbollah and Israel, fearing a larger war.

Netanyahu in his speech also may address a new China-brokered deal between Palestinian factions Hamas and Fatah to form a government together. The agreement was an attempt to resolve a rivalry that could make it even harder for Palestinians to secure a role governing Gaza whenever the war ends. Israel immediately denounced the pact, and State Department spokesman Matthew Miller called Hamas a terror group that should have no role in governing Palestinians.

Some Democrats are wary about Netanyahu, who used a 2015 joint address to Congress to denounce then-President Barack Obama's pending nuclear deal with Iran. National Security Adviser Jake Sullivan has said he does not expect Wednesday's speech to be a repeat of 2015's.

As the prime minister speaks, multiple protests are planned in and around the Capitol. The largest is set for Wednesday morning, with organizers planning to march around the Capitol demanding Netanyahu's arrest on war crimes charges. Relatives of Israeli hostages are planning a vigil on the National Mall.