Alan Dershowitz is a familiar name in media coverage and public conversation on an astounding variety of topics, but the subtitle of his latest book, “Defending Israel: The Story of My Relationship With My Most Challenging Client” (All Points Books), reveals what matters most to him.

Although the book was written before the president of the United States urged the prime minister of Israel to exclude two congresswomen from a congressional delegation to Israel, Dershowitz acknowledges that support for Israel — once a rare point of consensus in American politics — can no longer be taken for granted. Indeed, the whole point of his book is to make the case for Israel, which is exactly why Dershowitz refers to the Jewish state as his “client.”

While Dershowitz is careful to acknowledge that he has “no actual lawyer/client relationship with Israel,” he also embraces the moniker that has been bestowed on him by the pundits: “I have been called ‘Israel’s single most visible defender’ and ‘the Jewish state’s lead attorney in the court of public opinion.’ ” He insists that “I am free to criticize its policies when I disagree with them.” But he accepts the mantle of Israel’s public defender, and his new book can be seen as a kind of trial brief.

“If the drift away from bipartisan support for Israel is not reversed, it will pose real dangers to Israel’s security,” Dershowitz warns. “It is a goal of this book to try to influence, in a positive direction, this discernable drift away from bipartisan support for the Middle East’s only democracy and America’s most reliable ally. It is a daunting task, but a crucial one to help secure Israel’s future.”

“If the drift away from bipartisan support for Israel is not reversed, it will pose real dangers to Israel’s security. It is a goal of this book to try to influence, in a positive direction, this discernable drift away from bipartisan support for the Middle East’s only democracy and America’s most reliable ally.” — Alan Dershowitz

At the same time, “Defending Israel” is a memoir, both sentimental and poignant. Dershowitz was raised in a Jewish family in Brooklyn that “saw no conflict between their religious orthodoxy and their political liberalism, or between their Zionism and their progressive values.” At the age of 10, he challenged some of the rabbis in his Orthodox elementary school who believed that Jewish sovereignty must await the coming of the Messiah. Later, he attended a summer camp where his counselors included a 20-year-old Noam Chomsky, who “supported, in theory, a binational secular state” but “was not opposed in practice to the state declared by [David] Ben-Gurion.” (A couple of decades later, Dershowitz would publicly debate his former camp counselor over the Israeli-Palestinian conflict.)

Dershowitz is quick to point out the ironies that suffuse the current debate over Israel. The two-state solution, he reminds us, was explicit in the United Nations resolution that partitioned the British mandate over a territory called Palestine into “independent Arab and Jewish states.” The word “Palestine” itself was actually coined by the Roman conquerors of ancient Judea and referred to place, not a people. When Frank Sinatra sang at a fundraising concert in support of Jewish statehood at the Hollywood Bowl, the event was dubbed the “Action for Palestine” rally. “Had the new nation-state of the Jewish people called itself ‘Jewish Palestine,’ instead of Israel, the optics would be quite different,” Dershowitz quips.

Another irony is that Israel was far more popular in the early years of statehood, when it was seen as “weak, both militarily and economically, and it posed no danger to anyone.” Only after the Six-Day War in 1967 — and, a decade later, the electoral success of Menachem Begin and the Likud party — did the ground shift under Israel’s feet in world public opinion. “The election of Begin created some cognitive dissonance for many American Jews like myself and many of my friends and colleagues, who are both liberals and Zionists,” he writes. “We have had to confront this conflict over many years, and it may well continue into the foreseeable future.”

Significantly, Dershowitz was among the Jewish voices who spoke out in 1979 against the building of settlements on the West Bank. “We honestly believed, and I still believe, that building civilian settlements on the West Bank and in the Gaza Strip was harmful to Israel’s moral standing and did not contribute to its security,” he declares. Later, he joined in supporting “the Israeli equivalent of the ACLU” in challenging Israeli policies on civil liberties. And, only last year, he published the book “The Case Against BDS: Why Singling Out Israel for Boycott Is Anti-Semitic and Anti-Peace.”

“My position on Israel guaranteed me enemies on both the right and the left,” he explains. “The center, where I had located myself (center left in my case) was shrinking, and that movement toward extremes made reasoned, nuance discourse more difficult.”

Throughout his new book, Dershowitz enlivens his account with lively anecdotes that also remind us of the author’s friends in high places. When he told Arthur Goldberg that he was traveling to Israel to interview Prime Minster Golda Meir for a PBS broadcast in 1970, the former Supreme Court justice asked Dershowitz to do him a favor: “You have to bring Goldie a carton of Lucky Strikes unfiltered cigarettes as a gift from me and Dorothy,” Goldberg told Dershowitz. “She loves them, but her security people won’t let her have them.” When he sat down for a talk with Ariel Sharon, he was frustrated that Sharon spoke “as if reading from a scripted briefing.”

“ ‘Can we get down to tachlis?’ I asked, using a Yiddish term that roughly suggests, ‘Cut the B.S. and let’s get to the point,’ ” Dershowitz recalls. “He laughed and replied, ‘Good, I like tachlis.’ ”

Dershowitz has written more than 40 books and we can be sure he will continue to participate in what he calls “the communications war.” But there is a certain solemnity and gravity to his latest book, which serves as a charge to his fellow Americans and his fellow Jews. “We must determine our destiny, write our future history, and assure the survival of the Jewish people and their nation-state forever,” he concludes.

By “Defending Israel: The Story of my Relationship With My Most Challenging Client” on Amazon here.

Jonathan Kirsch, author and publishing attorney, is the book editor of the Jewish Journal.