Omar and Tlaib sparked the BDS controversy during a period when Donald Trump's administration has strengthened relations with Israel and slashed aid to the Palestinians
The support for a boycott of Israel by the first two Muslim women in the US Congress has opened a breach in the Democratic Party and threatens to create a fissure in the ironclad US-Israeli alliance.
Ilhan Omar and Rashida Tlaib made their debut in the House of Representatives in January openly declaring their support for the Palestinian-led Boycott, Divestment, Sanctions movement, or BDS.
The movement, launched more than a decade ago and modeled on the 1960s movement to pressure South Africa over apartheid, calls for people and groups to sever economic, cultural and academic ties to Israel, and to support sanctions against the Jewish state.
But for Israel partisans - including many Democrats and Republicans in Congress - BDS smacks of anti-Semitism and poses a threat to Israel.
Tlaib, 42, has Palestinian roots and represents a district of suburban Detroit, Michigan that is home to thousands of Muslims.
She argues that BDS can draw a focus on "issues like the racism and the international human rights violations by Israel right now."
Omar, 37, is the daughter of Somali refugees who was elected to represent a Minneapolis, Minnesota district with a large Somali population.
She accuses Israel of discrimination against Palestinians akin to apartheid, but denies that she is anti-Semitic.
Her remarks in January to Yahoo News however sparked anger among the large pro-Israel contingent in Congress, the powerful, largely Democratic US Jewish community, and Israel itself, where BDS is seen as a national threat.
"When I see Israeli institute laws that recognize it as a Jewish state and does not recognize the other religions that are living in it, and we still hold it as a democracy in the Middle East, I almost chuckle," she told Yahoo News.
"Because I know that if we see that in another society we would criticize it -- we do that to Iran, any other place that sort of upholds its religion."
Fissure among Democrats
Omar and Tlaib sparked the BDS controversy during a period when Donald Trump's administration has strengthened relations with Israel and slashed aid to the Palestinians.
But Republicans saw their support for BDS as both a threat to Jews and an exploitable rift among Democrats.
"Democrats have made it clear that hateful, bigoted rhetoric toward Israel is not confined to a few freshman members. This is the mainstream position of today's Democratic Party and their leadership is enabling it," Republicans said in a statement on January 29.
Republican Congressman Lee Zeldin urged his colleagues "to reject the anti-Israel and anti-Semitic hatred that we are starting to see infiltrating American politics and even the halls of Congress."