“For the first time since 1948, one of America’s two major parties has begun to abandon its commitment to Israel.”

So writes David Brog, executive director of Christians United for Israel, in an essay published online in the Winter 2013 edition of the conservative Middle East Quarterly.

Whatever he might think of President Barack Obama – in an interview this week with the Times of Israel, it didn’t come up – Brog is not talking about the president. Or about the current crop of Congressmen and Congresswomen.

“If you freeze the frame today, Congress is extremely pro-Israel. Israel very much enjoys strong bipartisan support on Capitol Hill,” he explains. “I’m not worried about Democratic Congressmen today.”

But, he continues, “I am worried about the Democratic Party in the future because we’re seeing this erosion among the base of the Democratic Party, the liberal base. We’re seeing it in polling, and we saw it very much on display at the mention of Jerusalem at the Democratic National Convention” in September.

That incident, in which delegates booed during a voice vote to reinsert both a reference to God and a reference to Jerusalem into the Democratic platform, “is a warning sign, and it’s a warning sign that pro-Israel progressives and pro-Israel liberals have work to do. They have a challenge to make Israel’s case in liberal terms to the liberal base.”

The challenge is borne out by figures from America’s college campuses. “If you freeze the frame today, America is a largely pro-Israel country. Polls show about two-thirds of Americans are what I call ‘pro-Israel,’ sympathize with Israel first and foremost. But there are warning signs about the future that we have to take seriously. You look over at Europe, and it’s flipped on its head. You have about one-third of Europeans expressing a similar sympathy for Israel. And you look on our college campuses, and you see it’s flipped on its head. About one-third of our students express a sympathy for Israel. And so you realize that there’s an enormous challenge out there. – unless you agree with this narrative that Israel alone is to blame for this conflict, we’ve got to make Israel’s case.”

Asked about CUFI’s criticism last week of a group of American Protestant leaders who called on Congress to cancel aid for Israel, Brog is quick to add that his group, too, has challenges to meet in making the case for Israel among American Christians.

“Each of us in the pro-Israel community has a specific task and a specific challenge,” he says. “When it comes to signs that there are conservatives turning against Israel, or Christians turning against Israel, I think that’s a job for us. We’re Christians United for Israel. That’s a challenge we need to take on. When there are signs of liberals and people on the Left criticizing Israel, abandoning Israel, that’s a challenge that our liberal friends, our progressive friends have to take on and worry about.”

But in each case, “we can’t just be complacent and say that because America is pro-Israel today, it will always be that way. Because I think the threats we’re seeing are very serious.

“You look at the polling. And I think it’s disturbing. The gap between parties is very, very wide when it comes to sympathy for Israel in this conflict. You look at the discourse on Israel on the main organs of liberal opinion and the main liberal blogs. It’s increasingly anti-Israel – and again, not in a nuanced way, but in a very black and white and superficial way that is troubling. So it was only a matter of time in my view until we saw this base express itself more aggressively within the Democratic Party.

“We saw it at the Democratic National Convention. We see it in the growing minority of Democratic members of Congress who refuse to sign on to pro-Israel legislation, who engage in critical letter-writing or legislation about Israel. I think the evidence is very, very clear that this is a problem that is only growing, only increasing.”

The problem isn’t unique to Democrats, he adds, only the timing.

“There was a time when the conservative movement was not so friendly to Israel,” Brog says. “There was a large body of opinion within the conservative world that was very critical of a strong US-Israel relationship. Had conservatives not taken them on, not argued in conservative terms to them the importance of supporting Israel, we could be facing a very different situation today in the Republican Party.”

But pro-Israel Republicans took on the challenge of making the case for Israel’s legitimacy among their own ranks.

“There’s a very good track record of conservatives taking on anti-Israel opinion [among their political allies] that has resulted in what we see today, which is very strong support. It’s not uncritical, but it’s very strong, solid support for Israel in the Republican Party. And that’s got to be the example, because today the problem isn’t on the right. Today the problem is on the left.”

The Left does not need to support particular Israeli policies or governments, Brog believes. The argument within the Democratic base is more fundamental.

“You either say, ‘Israel is guilty, so there’s no argument to be made [in Israel’s favor],’ or you say, ‘No, Israel’s struggle is legitimate, Israel’s right to exist is legitimate, Israel’s struggle for peace and security is legitimate. And we’re going to make the case for Israel before it is forgotten.’ It doesn’t have to uncritical, but that case has to be made.”