Israelis first heard about Ivanka Trump, daughter of the US Republican Party's nominee for US president, in June 2016, when a power struggle within Israel's rabbinate culminated in her eminent rabbi's name being removed from the list of acceptable authorities for conversion.

Among religious Israelis the question was: Rabbi Haskel Lookstein is no longer kosher enough? For everyone else, the question became: Donald Trump has a Jewish daughter?

Ms Trump, a 34-year-old mother-of-three, is married to Jared Kushner, the Orthodox son of New York real estate mogul Charles Kushner.

Kushner Jr, who owns the New York Observer, has also made millions from property deals.

Throughout a campaign marred by misogyny and antisemitism, Ivanka has served as her father's shield. And her marriage to Mr Kushner, a top Trump adviser, has reassured increasingly nervous US and Israeli Jews.

Why nervous? Donald Trump has accepted the endorsement of former KKK leader David Duke, and his supporters have no qualms about shouting "to the ovens!" at Jewish reporters.

For the many conspiracy-minded Trump backers, the media - seen as dominated by Jews and women - has become a prime target.

This week, social media was flooded with images of Hadas Gold, a reporter for Politico, with a bullet hole in her head. And after Julia Ioffe wrote a rather complimentary profile of Mr Trump's wife Melania in Gentleman's Quarterly last April, death threats forced her to live under police protection for weeks.

Jewish family or not, Mr Trump has not been above employing classic antisemitic tropes. This week, in what became known as the "global cabal speech", he railed against "a global power structure responsible for the economic decisions that have robbed our working class."

To all appearances, Mr Kusher does not mind. The FT reported this week that he was looking into establishing a post-campaign Trump TV network. Politico's Edward-Isaac Dovere tweeted: "It's so nice Jared Kushner's grandparents survived the Holocaust so he could look into a new TV network that would cater in part to Nazis."

The Jewish Kushners present a seemingly intractable conundrum. They are also a useful reminder: not every privately Jewish person will act as a Jew in the public sphere. He, or she, can be just as craven as the next.