The death of president George H.W. Bush brought Mikhail Gorbachev back into the news. The great former Soviet leader was commenting about Bush and the work they did together to end the Cold War.It brought back a reverie of memories.In the winter of 1993 I hosted Gorbachev at Oxford University. It was Hanukkah, the Jewish festival of lights. Introducing Gorbachev to the thousands of Oxford students who came to hear him were me and my student president, Cory Booker, an African-American Rhodes scholar who had become my closest friend.By now our story is well known.Cory and I studied Torah together almost daily, and the concepts we learned have become central themes in many of his public speeches, from the need to go beyond tolerance to the idea of mutuality and the interdependency of communities.But then came the Iran nuclear agreement and Cory’s support of it and the beginning of a downward spiral in his support for Israel that undermined much of our friendship and the Jewish community’s admiration for him. Nearly every time I attend a public event, people walk over to me and ask, “Why did Cory oppose the Taylor Force Act – which stops the funding of Palestinian terrorists – in Senate committee?” “Why did Cory condemn the moving of the American Embassy to Jerusalem?” And, “Why did Cory take a picture with BDS leaders who demand the removal of Israel’s wall that prevents suicide bombings?”But there we were in New York City this week, Hanukkah, exactly 25 years later, and Cory was speaking at “Never is Now,” ADL’s Annual Summit on Antisemitism and Hate, and he said this: “If you love someone, it’s not enough to sit back and watch and be a bystander. Love means that you have to be actively engaged in the affirmation of human dignity for all people. Love says, ‘It’s not enough to say I’m not racist.’ You have to be anti-racism. It’s not enough to say that ‘I’m not antisemitic.’ You must be anti-antisemitism.... We must stand up for each other and say that bigotry has no place, that antisemitism has no place.”A better summary of what harmed Cory’s relationship with the Jewish community in general, and me in particular, could not have been better articulated. And a better path for Cory to return to his convictions, amid his political ambitions, could not have been more eloquently offered. Cory needs to know that if you’re a United States senator from New Jersey, with a huge Jewish constituency, and the Iranians are threatening to kill all the Jews, you have to speak out. You have to condemn their antisemitism. You have a perch at the United States Senate. You have to go to the podium and say, “Look, whether or not I support the Iran nuclear deal is beside the point. I condemn in the strongest possible terms Iran describing the Jews as a cancer that must be eradicated.” And now that “moderate” Iranian President Rouhani has also called Israel a cancer – just like Ahmadinejad before him – it’s not too late for Cory to live up to his own words and condemn such wretched antisemitism.And when Louis Farrakhan gets up and says that Jews are termites – and we all know what you do with termites – then Cory needs to know that “it’s not enough to sit back and watch and be a bystander.... It’s not enough to say ‘I’m not racist.’ You must be anti-antisemitism.... We must stand up for each other and say that bigotry has no place, that antisemitism has no place.”So why didn’t Cory condemn Farrakhan?And since Cory was saying all this at the ADL – the premier antisemitism fighting organization in America, which CEO Jonathan Greenblatt has brought to new heights – why didn’t he practice what he preaches right there and then?We Jews are sick of being demonized. But we’re all sick of those who say that the demonization must end, but then refuse to condemn the antisemites lest they pay a political price.The confusion about my 25-year relationship with Cory is this. We studied hundreds – perhaps thousands – of hours of Torah together. He came to my home for perhaps hundreds of Friday night Shabbat dinners. We loved each other like brothers. And the Jewish community was inspired by our friendship, his beautiful speeches about the parsha we learned together, and our visits to Israel, and made him one of the single biggest recipients of Jewish political contributions in American history.So why the silence when the Jews are imperiled? TORAH IS sacred. It had to change both me and Cory. It certainly changed Martin Luther King, whose drawing on the beautiful themes of the Hebrew Bible made him the greatest American of the 20th century. King transformed the Torah into a liberation manifesto that powered the civil rights movement.A number of years ago, when visiting Memphis, Tennessee, and the Lorraine Motel with my children, at the site where King was assassinated 50 years ago this past April, I called Cory up and told him, “You have to see how beautiful the marble slab is which was placed right near where King died and the beautiful quote from the story of Joseph.” It appears in the Torah reading where Joseph’s brothers attempt to kill him. Cory quotes the story in a Facebook post of December, 2014: “They said to one another, ‘Behold, here cometh the dreamer.... Let us slay him... and we shall see what becomes of his dreams.’” Joseph’s brothers hated his visions. So they threw him in a pit and tried to murder him.King was the same. He dreamed a dream of racial equality which white supremacists hated. So they murdered him. But ultimately his dream won out among all people of fairness and decency, and King is today universally admired as a modern prophet who gave his life so that America would be cleansed of institutionalized racism.Now there is talk that Cory may be running for president.But there is a catch. America has become tired of politicians. And Cory is beginning to sound like a politician. Trump won the presidency because he was the straight-talking, anti-Clinton-politician-for-life model. And even those people who despise Trump might just despise the idea of career politicians even more. America is searching for authenticity.And if Cory is to be a serious candidate for the nation’s highest office, he has to go back to his roots and reclaim his convictions.It may not be popular to stand up for Israel in some quarters of American politics. But it’s what Cory actually believes. So he must do it.And it may not be popular to buck your party on legitimizing Iran while it calls for Israel’s annihilation. But Cory’s senior senator from New Jersey, Bob Menendez, did it. So Cory can, too.And learning Torah and repeating it for Jewish audiences – along with the Hebrew phrases that I taught him – comes with the obligation not just to impress audiences but to live by the Torah’s demands, to “act justly and to love mercy and to walk humbly with your God” (Micah 6:8), and, as Martin Luther King repeatedly said, to “let justice roll down as waters, and righteousness as a mighty stream” (Amos 6:8).The writer, whom The Washington Post calls ‘the most famous rabbi in America,’ is the international best-selling author of 30 books, including his most recent, The Israel Warrior. He served as rabbi at Oxford University for 11 years, where Cory Booker was his student president. Follow him on Twitter @RabbiShmuley.