Israel’s public campaign against the Iran nuclear deal has led to possibly the lowest point in the U.S.-Israel relationship, Phil Gordon, until recently the top White House advisor on the Middle East, said on Wednesday.

Speaking at a forum hosted by the Israel Policy Forum at the Harmonie Club in Manhattan, Gordon said that while an ongoing rift between the Israeli government and the Obama administration had existed before the nuclear deal was signed with Iran, the debate following the deal “has led to one of most polarizing and brutal U.S.-Israel relationship in history.”

The former WH official argued that the crisis that started with the unilateral invitation of Israeli Prime Minister Benjamin Netanyahu to address a joint session of Congress without notifying the administration “just felt different.”

Having an Israeli prime minister “vigourously oppose” the deal and turn Israel into a partisan issue was “possibly as rough as it has gotten between our two countries,” Gordon stressed. He went on to question “the tactics” of the way the government’s response to the deal has been approached, raising what would’ve been the consequences of the relationship if Congress would’ve managed to block the deal.

Gordon maintained that all along the way while the P5+1 was negotiating the deal, the frame work was designed to have Israel on the same page with the United States. But “it got to a point, and it was our assessment, that asking for some of the things Israel was insisting on meant no deal.”

Yesh Atid chairperson Yair Lapid, one of Israel’s leading opposition leaders, agreed with Gordon’s criticism of Netanyahu’s conduct. “I believe that the deal is problematic and dangerous. Israel rightly said that there could and should have been a better deal. But the process between the United States and Israel around this deal was problematic and mismanaged, ” Lapid told the 100 people gathered at the forum. “Israel has every right to express its opposition to the deal, but it wasn’t clear what was legitimate and what would be considered involvement in internal American politics… The dialogue was damaged, so Israel’s ability to influence the process and the agreement was harmed. With better dialogue Israel could have asked for, and received, the opportunity to examine the deal before it was signed. Not after.”

Going forward, Gordon, who is now a senior fellow at the Council on Foreign Relations, said that “it is time to turn the page.” Adding, “It feels to me that that is already starting to happen.”

Lapid, who is on a visit to the U.S. to meet with administration officials and Congress members to present his alternative vision on the the peace process, said that now that the deal is a fact, “We cannot allow the crisis with Washington to become a permanent fact of life.”

“Everyone has their own account for who is to blame, but we need to put this crisis behind us,” he said. “We need to start a process of healing and repairing, with the administration, with Congress, with the Democratic Party, with the American Jewish community. We don’t need to ask who is to blame but how do we fix it.

“That’s why I came to the United States at this time. To begin a different dialogue and to work on rebuilding and strengthening the special relationship between the United States and Israel,” he added.

While Lapid was presenting his plan for a new regional diplomatic initiative, Netanyahu was at his hotel making last minute changes to his speech at the UN General Assembly on Thursday.

Lapid has already announced that he plans to challenge Netanyahu in the next elections, he hopes will take place in 2016. He recently hired U.S. branding expert Adam Hanft to help craft his image and establish himself as a prime ministerial candidate. Hanft worked for President Barack Obama’s successful campaign in 2008 as an unpaid digital adviser.

The Yesh Atid leader met with former Saudi intelligence chief Prince Turki al-Faisal on Tuesday to discuss his regional peace plan, according to Walla News’ Amir Tibon.