Jerrold Nadler, a Democratic congressman from New YorkLauren Victoria Burke / AP

Updated on August 21 at 2:12 p.m. ET

President Obama, in a letter aimed at congressional Democrats wavering over supporting the nuclear deal with Iran, says the U.S. will maintain all options, including military force, should Iran pursue nuclear weapons.

“Should Iran seek to dash toward a nuclear weapon, all of the options available to the United States — including the military option — will remain available through the life of the deal and beyond,” Obama wrote in the letter obtained by The New York Times.

The letter dated August 18 is addressed to Congressman Jerrold Nadler of New York, and is aimed at Democrats who have concerns about the deal the U.S. and six world powers struck with Iran over its nuclear program. Here’s more from The Times:

While many of the promises have been made before by Mr. Obama, Secretary of State John Kerry and others, White House officials say the letter represents the first time that the president himself has compiled them under his name and in writing. It commits explicitly to establishing an office within the State Department to carry out the nuclear accord.

Congressman Adam Schiff of California, an influential Democrat who supports the deal, told The Times the president’s letter, in the words of the newspaper, “expanded assurances that sanctions lifted under the nuclear accord could be reimposed piece by piece, not all at once, to keep Iran in compliance.”

In the letter, also Obama pledged enhanced military cooperation with Israel, whose prime minister, Benjamin Netanyahu, has been a leading critic of the agreement. Netanyahu views Iran as an existential threat, and believes the Islamic republican cannot be trusted.

Nadler, whose congressional district in Manhattan includes a large Jewish population, told the Times he raised “troubling” questions about the U.S. ability to stop Iran from acquiring nuclear weapons, the U.S. commitment to Israel, and Iranian actions that Persian Gulf countries—and Israel—view as destabilizing. He later released a statement Friday saying he will support the deal. He wrote:

After carefully studying the agreement and the arguments and analyses from all sides, I have concluded that, of all the alternatives, approval of the JCPOA, for all its flaws, gives us the best chance of stopping Iran from developing a nuclear weapon. Accordingly, I will support the agreement and vote against a Resolution of Disapproval.

Congress has until September 17 to vote on the agreement that was struc in July. Obama has threatened a veto if lawmakers reject the historic accord, and it’s now becoming apparent that congressional opponents of the deal lack the 67 votes they need to override that presidential veto.

On Thursday, two Democratic senators—Claire McCaskill of Missouri and Joe Donnelly of Indiana—announced their support for the deal. That brings the number of Senate Democrats publicly supporting the deal to 26. Two Democrats, Charles Schumer of New York and Robert Menendez of New Jersey, say they will vote against it.  

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