Sen. Bernie Sanders’ (I-VT) foreign policy advisor Matt Duss, who was previously rumored to be under consideration for a position in the Biden State Department, is expected to remain with Sanders instead of making the move to Foggy Bottom, according to sources with knowledge of the matter.

This comes as Duss has boosted a series of tweets this week critical of the Biden administration’s handling of foreign policy issues, including the decision not to punish Saudi Crown Prince Mohammed Bin Salman over the killing of journalist Jamal Khashoggi and U.S. condemnation of the International Criminal Court’s decision to open an investigation into Israel. On Wednesday, Duss retweeted a post from Rep. Rashida Tlaib (D-MI) criticizing Secretary of State Tony Blinken’s opposition to a recently announced investigation into Israel’s actions in the West Bank and Gaza.

Some Hill staffers were skeptical that Duss was ever a serious candidate for a position in Foggy Bottom. “I think that was a progressive pipe dream advocated by the very far left and never seriously considered by Biden or Blinken,” one congressional staffer, who asked to remain anonymous, told JI.

This week, the Sanders advisor started distributing a letter authored by Sanders to other Senate offices calling on Blinken to urge Israeli officials to do more to assist in the vaccinations of Palestinians living in the West Bank and Gaza.

The letter argues that Israel is responsible for aiding the Palestinians in the pandemic under the Geneva Conventions, even though the Oslo Accords gave the Palestinian Authority responsibility for health services in the Palestinian territories. Israeli officials and some in the pro-Israel community in the U.S. have pointed to the Oslo Accords to argue that Israel is not obligated to provide vaccines for Palestinians. Sen. Elizabeth Warren (D-MA) is the only other senator that has signed onto the letter, which closes next week.

View the full text of the letter here.

The letter also argues that the current situation emphasizes the need to “clarify the status of the West Bank and Gaza Strip as territory occupied by Israel” and ultimately end the occupation of the Palestinian territories and establish an independent Palestinian state.

Sanders said last week it was “outrageous” that Israeli Prime Minister Benjamin Netanyahu provided vaccines to foreign allies before supplying the Palestinians.

At the same time as Biden’s pick to oversee the Office of Management and Budget, Neera Tanden, was under fire for inflammatory tweets about Democratic and Republican legislators and policies, Duss was markedly more reserved on social media, going so far as to delete a tweet sharing congressional candidate Nina Turner’s answer to a Jewish Insider questionnaire. The deleted tweet highlighted Turner’s support for conditioning aid to Israel, a significant foreign policy issue during the last Democratic presidential primary. Turner served as campaign co-chair of Sanders’ 2020 bid.

Aaron David Miller, a senior fellow at the Carnegie Endowment for International Peace, told JI, earlier this week, “After what happened to Neera Tanden and given what Colin Kahl’s going through, if I were under serious consideration for a senior position — whether it required confirmation or not — the last thing I’d be doing is a whole lot of tweeting on any issue, let alone hot button ones.”

Kahl, Biden’s nominee for under secretary of defense for policy, faced intense scrutiny at his confirmation hearing Thursday over his past tweets criticizing Republicans.