Two more Democrats in the U.S. Senate have announced support for the Iran nuclear deal as allies of President Barack Obama inched toward their goal of ensuring Congress cannot kill the deal.
The addition of senators John Tester of Montana and Al Franken of Minnesota brings the total of Senate Democrats who have declared their support to 18, a little more than half of the 34 votes needed to uphold Obama's expected veto of a resolution of disapproval Republican leaders are preparing to send him next month.
"It isn't a perfect agreement," Franken said. "But it is a strong one. This agreement is, in my opinion, the most effective, realistic way to prevent Iran from getting a nuclear weapon anytime in the next 15 years."
Tester, a so-called red-state Democrat representing voters who typically vote for Republican presidents, agreed. "It's clear this deal is the only option right now to stop Iran from developing a nuclear weapon," he said.
The endorsement of Tester, who is chairman of the Democratic Senatorial Campaign Committee, may be particularly valuable to the White House as it indicates that he feels safe voting for the deal despite coming from a conservative state.
Tester had been targeted by a tough television commercial produced by Vets Against the Deal, featuring an Iraq War veteran who was badly wounded by a blast from an Iranian-made bomb.
"Every politician who is involved in this will be held accountable. They will have blood on their hands," says retired Staff Sargeant Robert Bartlett in the ad, his facial scars showing prominently.
But so far a barrage of ads against the deal have had surprisingly little effect. Another Democrat targeted by groups opposing the deal, Senator Joe Manchin of West Virginia, is feeling "no pressure at all," said Manchin spokesman Jonathan Kott, adding that his boss is leaning toward supporting the agreement.
That comes as good news for the White House, which has held out little hope of winning over Republicans or Democrats from conservative states like Montana and West Virginia.
The White House strategy has aimed mainly at culling votes from liberals like Franken, who overwhelmingly prefer a negotiated deal over continued economic confrontation with Iran and possibly military conflict if the deal breaks down.
Chicago Mayor Rahm Emanuel, a former chief of staff at the Obama White House, also threw his support behind the deal August 12. Although he does not have a vote in Congress, his endorsement could help win over wavering legislators.
"This agreement is a good agreement, and it is far superior to either sustained bombing that would never actually get you what you have today, or sanctions that would exist on paper but with no international support," Emanuel told The Huffington Post.
Despite the spate of announcements in favor of the deal, House Majority Leader Kevin McCarthy claimed that Republicans still have a strong possibility of getting enough votes to override a presidential veto of the resolution of disapproval they are planning to start debating in the House September 8.
McCarthy, who is visiting Israel on an annual congressional trip, questioned the White House strategy of relying on the support of just over one-third of Congress -- the number needed to sustain a veto -- for a major diplomatic agreement.
He noted that the U.S. Constitution requires the president to get a two-thirds vote of approval in the Senate to ratify foreign treaties -- a high hurdle that Obama avoided by not designating the Iran deal as a treaty, though some in Congress thought he should have.
"Now he's playing to hold one-third. If you try to make an agreement where only the minority of your country is going to support [it], that majority is going to have a voice one day," McCarthy warned.
He predicted that the deal would "play very large" in the 2016 presidential race.
Nearly all the Republicans in Congress are expected to vote against the deal and GOP presidential candidates have unanimously rejected it, with some vowing to repeal the deal as one of their first acts in the Oval Office.