It rolls so trippingly on the tongue: Israel, the Jewish and democratic state. That’s the Israel most Americans say they support, with equal emphasis placed on both sides of the equation.

I didn’t realize quite how tenuous the Jewish state’s hold on its democratic side was until I heard local pundit John Rothmann interview Yohanan Plesner, president of the Israel Democracy Institute, at Congregation Emanu-El in San Francisco.

“Very few people understand how fragile Israeli democracy is,” Plesner told the crowd.

In the absence of a constitution to protect the basic norms and values of Israel’s democratic culture, much of what makes it so special could be overturned by the Knesset. Even the so-called Basic Laws, which govern such fundamental state structures as the military and electoral procedures, could be threatened by a simple majority vote in Israel’s parliament.

When we say democratic, we’re not talking about the nation’s liberal characteristics, such as tolerance of diversity, racial equality, or rights for the Reform and Conservative Jewish streams — you know, the things most American Jews like. Without a constitution, those are the happy beneficiaries of Israel’s democracy only as long as they are favored by a parliamentary majority, which means the next parliament can get rid of them — and that’s exactly what’s beginning to happen already, with the new Knesset backpedaling on progress made by the previous one in such areas as conversion reform.

Until quite recently, coming up with a constitution for Israel was a main priority for the IDI. No longer, Plesner told me after his talk. That’s because most Israelis don’t see it as a priority.

“For the Israeli public, the idea of a constitution is a technical issue,” he said.

Not only that, he added, but given the rightward shift in the current Knesset, it’s a bad time to bring the notion to legislators. “It has no political viability,” he said. “It would require serious effort to build consensus, and it’s just not there right now.”

The Israel Democracy Institute, a nonpartisan think tank founded in 1991, isn’t as known to the American Jewish community as other organizations, such as Magen David Adom or the Jewish National Fund. It doesn’t save lives or make the desert bloom. What it does, in its quiet, unsexy way, is work to strengthen the foundations of Israeli democracy through research, policy reform, good governance, building consensus and promoting civil liberties.

I said it wasn’t sexy.

But its work is recognized as highly effective, and essential to Israel’s well-being. Awarding it the Israel Prize for 2009, the prize committee said IDI had “the greatest professional and public influence on the constitutional and democratic discourse in Israel.” It is able to have that impact precisely because it is not a champion of the left or the right, but, as Plesner explains, “sees its role as preventing the erosion of the shared values component” of Israeli society.

“The worst thing we can do is set our Jewish character in opposition to our universal, democratic character. Our goal is to show that the combination can work: You can be a believing Jew, and believe in full equality.”

Plesner spoke about the attacks made on some of Israel’s Basic Laws during the last Knesset, which lasted from 2013 until this past March. There were “dozens of pieces of legislations” put forth, he said, “aimed at skewing the balance between the democratic and Jewish nature of the state.”

One concerted effort looked to weaken the Supreme Court, in effect shoring up the power of the prime minister and the Knesset. In a country without a constitution, the power of the court to review legislation “is critical,” he told the San Francisco crowd. Other proposed bills took aim at freedom of the press, free speech, the status of Israel’s Arab minority — the list went on.

Very few of those initiatives passed, he said, calling them “empty rhetoric.” But, he added, “we expect more of them this session.” Nevertheless, he is sanguine about the future and said Israel remains “a vibrant, lively, functioning democracy.”