Washington, July 18 (RHC)-- A bipartisan coalition of more than 100 former U.S. diplomats has written to U.S. President Barack Obama, pledging support for the “negotiated agreement” with Iran over its nuclear program.

“If properly implemented, this comprehensive and rigorously negotiated agreement can be an effective instrument in arresting Iran’s nuclear program,” the former diplomats wrote, according to The Hill. The letter is seen as a major boost to the Barack Obama administration’s campaign to sell the Iran accord to a skeptical Congress as well as the American public.

“In our judgment the [plan] deserves Congressional support and the opportunity to show it can work,” added the signatories, who include former ambassadors to Israel, Russia, Iraq and the United Nations.

Critics -- especially Republican lawmakers, a number of Democrats, Israel lobby and Israeli Prime Minister Benjamin Netanyahu -- have lambasted the nuclear accord, warning that it will only clear Iran’s path to a nuclear bomb.

Senator Mark Kirk, one of the key architects of Iran sanctions in the Senate, said the Obama administration “sold out” Israel on the nuclear agreement with Iran. “This agreement condemns the next generation to cleaning up a nuclear war in the Persian Gulf,” the Republican from Illinois said on a radio program. “It condemns our Israel allies to further conflict with Iran.”

U.S. presidential candidate and Republican Sen. Lindsey Graham described the accord as "a possible death sentence for Israel" which will "make everything worse." House Speaker John Boehner criticized President Obama for abandoning “his own goals” in nuclear talks with Iran. In a statement after the conclusion of talks, the Ohio Republican warned that the agreement “is likely to fuel a nuclear arms race around the world.”