By Patricia Zengerle
WASHINGTON (Reuters) - U.S. Senator Ben Cardin said on Friday he would vote against the nuclear agreement with Iran, lessening the chances that President Barack Obama can win enough votes to avoid having to use his veto power to protect the international agreement.
"This is a close call, but after a lengthy review, I will vote to disapprove the deal," Cardin, the top Democrat on the influential Senate Foreign Relations Committee, said in an opinion column to be published in The Washington Post.
The Maryland lawmaker became the third Senate Democrat to announce his opposition. The others, Charles Schumer of New York and Robert Menendez of New Jersey, came out against it last month.
But the "yes" list in the Senate reached 38 on Friday, as Michael Bennet of Colorado announced his support for the deal. All of the lawmakers in favor are Democrats or independents who generally vote with them.
That left just five of Obama's fellow Democrats in the chamber undecided, including Richard Blumenthal of Connecticut, Maria Cantwell of Washington, Joe Manchin of West Virginia, Gary Peters of Michigan and Ron Wyden of Oregon.
Under a law co-written by Cardin and signed by Obama in May, Congress has until Sept. 17 to vote on a "resolution of disapproval" of the nuclear agreement, announced on July 14 between the United States, five other world powers and Tehran.
If such a resolution passed Congress and lawmakers overrode Obama's promised veto, it would weaken the nuclear deal by eliminating the president's ability to waive many sanctions on Iran, a key component of the pact.
When Cardin's fellow Maryland Democrat, Barbara Mikulski, became the 34th senator supporting the deal on Wednesday, Obama was assured that Congress would sustain a veto. Deal opponents need two-thirds majorities in both the 100-member Senate and 435-seat House of Representatives to override a veto.
HOPE FOR 41
Deal supporters have been hoping to muster 41 Senate votes to use the filibuster procedural rule to block a vote on a disapproval resolution in the Senate and keep Obama from having to use his veto.
Cardin's announcement makes that target a more difficult one, more so as a spokesman for Manchin said he had decided he would not support a filibuster, although he has yet to make up his mind about the nuclear agreement itself.
Lawmakers will begin to consider the resolution of disapproval as soon as they return from their August recess on Tuesday. The first vote in the House of Representatives is expected next week and the Senate could also begin voting as soon as next week.
With Republicans virtually united in opposition, Democrats have spent the past two months rallying support for an agreement seen as a potential legacy foreign policy achievement for the president.
Bennet, like many other lawmakers who support the pact, said it is not perfect but seems like the best way to keep Iran from obtaining a nuclear weapon.
"Our primary objectives are to prevent Iran from having a nuclear weapon, make sure Israel is safe and, if possible, avoid another war in the Middle East," Bennet said in a statement. "This agreement represents a flawed, but important step to accomplish those goals."
No Republican in either the House or Senate has backed the nuclear deal.
One Republican seen as a possible deal supporter, Republican Senator Susan Collins of Maine, is expected to announce her position after Congress returns to Washington next week.
(Reporting by Patricia Zengerle; Editing by Peter Cooney, Susan Heavey and Steve Orlofsky)