On Tuesday, the House overwhelmingly passed a resolution condemning the campaign, the Boycott, Divestment and Sanctions movement. With its adherents prominent in the British Labour Party and critics fighting it in Washington and dozens of state capitals, B.D.S. has become a proxy for the Israeli-Palestinian conflict in the United States and Europe, with all the emotion the conflict stirs.

The movement’s supporters are routinely accused of anti-Semitism. Opponents are accused of trampling on free speech. Yet B.D.S. is often misunderstood and misrepresented by people on both sides. Is it a legitimate, nonviolent protest to protect the rights of Palestinians, or a movement that aims to eliminate Israel and traffics in anti-Semitism?

Here are answers to some of the most difficult questions.

What is B.D.S.?

The B.D.S. movement seeks to mobilize international economic and political pressure on Israel in solidarity with the Palestinians. Modeled on the fight against the apartheid regime in South Africa, it calls for countries, businesses and universities to sever ties with Israel unless it meets three demands:

• Ending its occupation of all land captured in 1967 and dismantling the wall and fence that separate Israel from much of the West Bank, dividing many Palestinian neighborhoods.

• Granting “full equality” to Palestinian citizens of Israel.

• Assuring the right of Palestinian refugees and their descendants to return to the homes and properties from which they or their ancestors were displaced in the wars that led to the establishment of Israel in 1948.

Many who embrace B.D.S. see it aimed primarily at ending Israel’s occupation of the West Bank. Its demands sound innocuous enough: Israel already claims to give its Arab citizens equal protection under the law. Withdrawing from Palestinian territory would create space for a coherent Palestinian state. The fate of Palestinian refugees would have to be addressed in any ultimate resolution.

In an interview, Omar Barghouti, a top B.D.S. spokesman, called the Israeli laws racist and exclusionary. A democratic state could still provide asylum for Jewish refugees, showing “some sensitivity to the Jewish experience,” he said, “but it cannot be a racist law that says only Jews benefit.” Asked if that means Jews cannot have their own state, he said, “Not in Palestine.”

Who is behind it?

B.D.S. describes itself as a loosely connected, nonhierarchical network of activists, though coordination is provided by the Palestinian B.D.S. National Committee, of which Mr. Barghouti, a Palestinian resident of Israel, is a co-founder.

A host of affiliated groups lead the charge for B.D.S., such as Students for Justice in Palestine and Jewish Voice for Peace in the United States, the Palestine Solidarity Campaign and War on Want in Britain, and the World Council of Churches in Europe.

Within the West Bank and Gaza, sponsors include a broad coalition of unions and nongovernmental organizations. B.D.S. enjoys at least the tacit support of a large majority of Palestinians, according to Khalil Shikaki, a Ramallah-based pollster.

Elsewhere, it appeals to those, including a significant number of politically liberal Jews, who are frustrated by the Israeli occupation of the West Bank, and the blockade and frequent bloodshed in Gaza.

Is B.D.S. anti-Semitic?

Leaders of B.D.S. insist that it is not anti-Semitic, and the movement’s umbrella group explicitly rejects anti-Semitism.

But many Israelis and American Jews say it is, using the so-called three-Ds test to distinguish fair criticism of Israel from anti-Semitism: Does the criticism delegitimize Israel, apply a double standard or demonize it?

B.D.S. does all three, its critics say, by questioning Israel’s right to exist, and by singling out Israel for its treatment of Israel’s Arab citizens when minorities in some countries suffer far more. The columnist Ben-Dror Yemini, a critic of the movement, said B.D.S. supporters also demonize Israel when they portray the country as “the great danger to humanity.”

Rebutting the double-standard charge, B.D.S. leaders say that Palestinians fighting for their own rights should not be expected to give equivalent attention to abused minorities elsewhere. And Kenneth Stern, director of Bard College’s Center for the Study of Hate, urges a distinction between effect and motivation: Palestinians who feel no ill will toward Jews but yearn for self-determination in the land of their forebears may rightly argue that to disparage that yearning is a form of bigotry.

Is B.D.S. anti-Zionist?

Yes, loudly and proudly. Its founding documents explicitly reject Zionism — the belief in self-determination for the Jewish people in the biblical land of Israel — calling it the “ideological pillar of Israel’s regime of occupation, settler colonialism and apartheid.”

“A Jewish state in Palestine in any shape or form cannot but contravene the basic rights of the indigenous Palestinian population and perpetuate a system of racial discrimination that ought to be opposed categorically,” Mr. Barghouti said.

Is it nonviolent?

In its original 2005 call, B.D.S. urged strictly “nonviolent punitive measures,” and Mr. Barghouti said B.D.S. “considers violence targeting noncombatants as illegal and immoral.” Still, he said, B.D.S. treats resistance to what it sees as Israeli oppression, including by armed struggle, as a legitimate right. Asked if B.D.S. condemned violence that targeted Israeli soldiers, he declined to comment.

Opponents have attacked B.D.S. not just for failing to condemn violence but for allowing terrorists and their supporters under its umbrella. The B.D.S. National Committee’s members, for example, include the Council of National and Islamic Forces in Palestine. The council includes several groups designated by the United States as terrorist organizations, including Hamas, Palestinian Islamic Jihad and the Popular Front for the Liberation of Palestine.

How does B.D.S. propose to solve the Israeli-Palestinian conflict?

It does not. B.D.S. does not advocate for any specific outcome.

Critics say B.D.S. is actually counterproductive to resolving the conflict, because it rejects Israel’s right to exist in spite of settled international law; encourages Palestinians to insist on the right of return for all refugees, which Israel is unlikely to ever accept in negotiations; pressures only one side to make concessions; and discourages bridge-building efforts between Israelis and Palestinians on the grounds that they “normalize” Israel. They say its rejection of the Jewish state distracts from debate over how to end the conflict and plays into the hands of right-wing Israeli opponents of a Palestinian state.

How entrenched has B.D.S. become in the United States?

As an organized movement, not very. B.D.S. does not appear especially well financed, its leadership is atomized and at the grass-roots level even its most enthusiastic backers do not always agree on what they are trying to achieve. Still, the idea has significant support, and may be gaining ground. A survey released in February suggested that one in five Americans approved of B.D.S. as a way of opposing Israeli policy toward Palestinians. A December 2018 University of Maryland poll of a much larger sample put support at 40 percent.

Actual accomplishments have been minimal: a few dozen resolutions in university student assemblies; a handful of decisions by law-enforcement agencies to stop training with the Israeli military; votes by two faculty groups last year — the Association for Asian American Studies and the larger American Studies Association — for limited boycotts of Israeli academia.

Opponents of B.D.S. have more to show for their efforts. Legislatures in at least 26 states have passed laws barring government agencies from contracting with or investing in companies that support B.D.S. In New York, Gov. Andrew Cuomo signed an executive order to that effect in 2016.

The state laws are being challenged in the courts, where opponents argue that they impinge on free speech. Some of the state laws have been struck down for violating the First Amendment.

The Republican-led Senate approved a federal version of an anti-B.D.S. bill in February that would allow state and local governments to break ties with companies that join the boycott. The House passed a weaker version on Tuesday, condemning B.D.S. but with a nonbinding resolution that left out the controversial measure allowing governments to boycott companies that support the movement.

Is there a link between the resurgence of anti-Semitism in Europe and B.D.S.?

Anti-Semitism has increased in Europe because of numerous factors, including globalization, populism, loss of national identity and the perceived oppression of Palestinians by Israel. A growing Muslim minority, mostly from North Africa, has viewed Israeli policies toward the Palestinians as anti-Muslim, leading many to support B.D.S.

There is some overlap between support for B.D.S. and anti-Semitism.

But while the European Union and some member states have introduced labeling requirements for products from the occupied West Bank and have denied funding to academic institutions in West Bank settlements, B.D.S. has had very little impact outside university settings.

Generally there has also been far less political pushback to B.D.S. in Europe than in America, partly because Jews in Europe are fewer and less organized than in the United States. European countries have strict nondiscrimination laws that would make official adherence to B.D.S. difficult.

Is B.D.S. working?

In the most tangible ways, not so much. Despite scattered pullouts from Israel by some companies, foreign direct investment in Israel is at an all-time high. Israel’s economy is well-suited to resist boycotts because it is less dependent on exports of commodities, which can be sourced elsewhere, than on sales of intellectual property, like software, and business-to-business products, against which it is harder to mobilize consumers. And while Ireland advanced legislation to ban imports of goods produced by Israeli settlements on the West Bank last year, the B.D.S. movement acknowledges that few foreign governments have imposed sanctions on Israel.

Reputational damage is harder to quantify, and B.D.S. frequently scores public-relations victories: The singer Lana Del Rey pulled out of a Tel Aviv music festival last year and the Argentine national soccer team canceled a match in Israel. But an effort to boycott the Eurovision song contest in Israel in May failed to make much of a dent.

How do Israelis view B.D.S.?

Not kindly, though some are happy to exploit it.

Many in what is left of the peace camp support a targeted boycott of settlement products, but see a boycott of all of Israel as unacceptable.

Israel’s government has embraced two seemingly opposing views, boasting on the world stage that B.D.S. is having no effect while warning Israelis that it is a strategic threat. In domestic politics, exaggerating the threat of B.D.S. adds to the sense that Israel is besieged and that the Palestinians are not really interested in peacemaking, bolstering right-wing arguments for continued expansion of Jewish settlements in the West Bank.