Several former advisers to President Barack Obama have rejected the likely terms of a nuclear deal with Iran, adding their names to an open letter that declares: “The agreement will not prevent Iran from having a nuclear weapons capability.”

The letter, published on the website of the Washington Institute for Near East Policy, concludes that the known terms of the Iran deal will “fall short of meeting the administration’s own standard of a ‘good’ agreement.”

A good deal must, they write, include monitoring and verification at all nuclear sites in Iran, including military ones; rule out possible military dimensions of Iran’s nuclear program before sanctions are lifted; limit Iran’s development of advanced centrifuges; hold back sanctions relief until Iran complies with all terms; and prepare new sanctions in the event that Iran does not honor the deal.

Until a better deal is made, the signatories recommend extending–though not expanding–current sanctions.

The list of 18 signatories includes some Republicans, and known hawks such as former Sen. Joseph Lieberman (I-VT). However, as the New York Times points out, it also includes some of Obama’s most senior first-term policy advisers:

Among them is Dennis B. Ross, a longtime Middle East negotiator who oversaw Iran policy at the White House during the first Obama term; David H. Petraeus, the former C.I.A. director who oversaw covert operations against Iran until he resigned two years ago; and Robert Einhorn, a longtime State Department proliferation expert who helped devise and enforce the sanctions against Iran.

Also signing the letter were Gary Samore, Mr. Obama’s former chief adviser on nuclear policy who is now the president of the advocacy group United Against Nuclear Iran, and Gen. James E. Cartwright, a former vice chairman of the Joint Chiefs of Staff and an architect of Mr. Obama’s effort to build up military forces in the region.

Notably, the letter is also signed by Norman Eisen, the most recent U.S. ambassador to the Czech Republic, who was a senior Obama White House staffer and founded the left-leaning Citizens for Responsibility and Ethics in Washington.

The letter comes in the wake of similar comments by former Secretary of Defense William Cohen, who served during Bill Clinton’s second term. Cohen told a group of Bloomberg reporters on Wednesday morning that President Obama’s intent may have been to stop nuclear proliferation, but the terms of the pending Iran deal made nuclear proliferation more likely.

Cohen also noted that Obama’s weak approach to Iran had caused great nervousness among U.S. allies in the Middle East.