WASHINGTON — Alan Dershowitz wants in — to the “Community of Yes,” J Street’s new campaign to rally broad-based American support for meaningful presidential leadership to end the Israeli-Palestinian conflict.

We believe that a major presidential effort will be required to achieve our goal — ensuring Israel’s security and future as a Jewish and democratic home — and that such an effort will require political will and guts. The campaign aims to show that the mainstream of Americans, Jewish and non-Jewish, will support a major push to forge a rational resolution to the conflict.

In an ad supporting the campaign, we highlighted the choice that faces the president between those who say “yes” because they believe a two-state resolution to the conflict is an urgent priority and those who will say “no” and aim to raise the political costs for supporters of bold American action.

So where does Dershowitz fall?

He does support the notion of a two-state solution and, thankfully, nearly the entire Israeli political spectrum also has publicly affirmed the notion. But what about a bold effort by the president to end the conflict, including perhaps outlining publicly the parameters of what a two-state solution would mean?

On April 21, Alan Dershowitz, under the headline “J Street can no longer call itself pro-Israel,” wrote in the Huffington Post that J Street had “gone over to the dark side” for saying that “resolving the [Israeli-Palestinian] conflict is not only necessary to secure Israel’s future, but also critical to regional stability and American strategic interests.”

In a debate with me last November, he claimed that by advocating for vigorous U.S. leadership and airing our differences with the Israeli government, J Street is “diluting” the voice of American Jews and “creating a false picture” of what the Jewish community thinks.

The reality, of course, is the opposite: We are giving voice to the large number of pro-Israel, pro-peace Jewish Americans and others who have been silenced on this issue for too long.

Then, in June, Dershowitz headlined a fund-raiser for the Tea Party-friendly opponent of U.S. Rep. Jan Schakowsky (D-Ill.). Schakowsky — a progressive Jew and longtime staunch supporter of Israel — supports President Obama’s approach to the Middle East and has been endorsed by JStreetPAC for backing a sensible pro-Israel, pro-peace agenda.

Dershowitz’s candidate says he’s running against Schakowsky’s for “failing to speak out” against the Obama administration on Israel — and Dershowitz is backing him in the debate, not Schakowsky.

The “Community of Yes” is designed to encourage Americans to “speak out” as well — albeit in a different direction. We seek to rally those who favor more presidential leadership to forge a two-state solution to the Israeli-Palestinian conflict that ensures Israel’s future as a democratic home for the Jewish people, creates a viable Palestinian state and promotes America’s vital national interests.

Yet that’s precisely the sentiment that provoked Dershowitz to call J Street not pro-Israel, and it’s the opposite of the position Dershowitz is endorsing by standing behind Schakowsky’s right-wing opponent.

I’ve written before that Alan Dershowitz’s mode of advocacy for Israel represents what is wrong with the way the “case for Israel” has been made for far too long. It is emblematic of what Peter Beinart recently called “the failure of the American Jewish establishment” to make room in the communal tent for the more progressive, liberal wing of the Jewish community that loves and supports Israel but isn’t ready to check its values at the door when it relates to Israel.

It is the style of Dershowitz’s advocacy — labeling us the “dark side,” calling us “McCarthyist” — that cements his position as part of the “Chorus of No” that is working hard to frighten American policymakers and politicians from speaking out openly and frankly on issues related to Israel and the Middle East.

I respect Alan Dershowitz. I agree with some of his views on Israel and the Middle East. But I believe that how he defines what it means to be “pro-Israel” and the manner in which he advocates is precisely what is making it so unattractive for many people in our community — particularly the young people — to be “pro-Israel.”

Alan, tell me you won’t attack me as “not pro-Israel” for saying that resolving the Israeli-Palestinian conflict is a vital American interest, or for criticizing Israel’s approach to Gaza or for calling on the president to make an even stronger effort to achieve a two-state solution — and I will gladly admit I was wrong. And we’ll happily spring for the cost of remaking the ad to exclude your two-second cameo in the “Chorus of No.”

Jeremy Ben-Ami is the president and founder of J Street.