Such language would be a big shift for the Democratic Party, which has been reluctant to criticize Israel, a U.S. ally. But adding it now is vital both to guide policy and to contrast with President Donald Trump, whose administration has greenlighted hardline Israeli policies, the foreign policy experts argue in their message, an advance copy of which was shared exclusively with HuffPost.

The group wants the party and its presumptive presidential nominee Joe Biden to loudly oppose unilateral Israeli annexation of land in the West Bank, the area that would be integral to a full-fledged Palestinian state, as well as Israel’s military occupation of that region and its policy of building Israeli settlements there.

Crafting a response will be complex for him. Republicans increasingly claim that the Democratic Party is abandoning Israel. Trump even said last year that American Jews, most of whom vote Democratic, are showing “either a total lack of knowledge or great disloyalty.” Democrats don’t want Republicans to seize another chance for an attack, but most want to defend the long-standing American goal of helping create two coexisting states of Israel and Palestine to prevent continued violence, repression and hatred.

The right strategy is to be clear about what Democrats stand for, the former officials say.

“Past party platforms have rightly stated a commitment to Israel’s security and included condemnations of threats and actions against our ally,” their letter reads. “Those platforms have, however, also been nearly silent on the rights of Palestinians, on Israeli actions that undermine those rights and the prospects for a two-state solution, and on the need for security for both peoples.”

“We ask that the platform … make clear what a comprehensive effort to achieve a two-state solution to the Israeli-Palestinian conflict should look like under a future Democratic administration, which includes a commitment to security, democracy, and human rights,” it continues.

Signatories include Avril Haines and Ben Rhodes, top officials under former President Barack Obama in what the likely Democratic nominee calls the “Obama-Biden administration,” and key advisers to Biden’s rivals for the 2020 Democratic nomination, like Doug Wilson, who worked for former South Bend, Indiana, mayor Pete Buttigieg, and aides to Sens. Elizabeth Warren (D-Mass.) and Bernie Sanders (I-Vt.). High-ranking former diplomats who have worked on Israel and Palestine like Martin Indyk and Strobe Talbott are also among the group.

If Democrats do adopt the positions endorsed by the letter in the upcoming conversations about the party’s latest platform, they would be breaking with more conservative members of the party who have long argued it’s too politically risky to get into specifics on Israel and Palestine. In 2016, Democratic Party leaders declined to criticize either the occupation or the settlements. At the time, former California Rep. Henry Waxman said, “Those who litigate the particulars of a two-state solution between the Israelis and Palestinians by fighting for controversial language in the Democratic platform are severely misguided.”

For traditionally cautious foreign policy veterans to now advocate for that approach shows the way U.S. political discourse around the issue and Democrats’ expectations of their party have evolved.

As Trump has reshaped U.S. policy to favor Netanyahu and pressure Palestinians to accept a future state that’s much reduced from what they have long envisioned, right-wing Israelis and their supporters have become more ambitious in challenging the traditional Middle East peace process. Meanwhile, the Trump administration’s capitulations to Israel and the nation’s extreme moves have energized activists who want a more even-handed American approach.

Biden has repeatedly said he will not support annexation and highlighted his concern for Palestinians in messages in recent months to two major groups working on Israel policy, J Street and the American Israel Public Affairs Committee. But he’s trying to balance the different parts of his potential coalition of voters.

Last week, he said he would preserve one of Trump’s biggest gifts to Netanyahu: U.S. acknowledgment of Jerusalem as Israel’s capital, a step that American policymakers have long said should not take place until a peace deal is in place that acknowledges Palestinians’ claims to the historic city.

Biden’s circle includes figures who opposed the 2016 push for a sea change in the platform like former Hillary Clinton aide Jake Sullivan. Still, activists believe their thinking may have evolved because of Trump’s policies and increasing awareness among liberals, encouraged by Sanders, of Netanyahu’s often aggressive treatment of the Palestinians.

The Monday message echoed a petition circulated by J Street, a liberal Jewish organization that promotes a two-state solution for the Israelis and Palestinians. In March, the campaign secured signatures from more than 200 Jewish leaders for the same message and sent it to both the Republican and Democratic national committees.

Similar groups, lawmakers and powerful U.S. allies have warned Netanyahu that annexation threatens international support for Israel.

Read the letter and the list of signatories below: