JERUSALEM — In a matter of months, a campaign to boycott Israel has moved from the margins of politics — liberal college campuses and protest marches — to Congress, where the freshman Representatives Ilhan Omar of Minnesota and Rashida Tlaib of Michigan have become its most vocal backers, drawing fire from the White House.

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.