(Bloomberg) — Obama administration objections to a letter
sent by 47 Republicans to Iranian leaders hasn’t shaken support
for legislation that would give lawmakers a say on any deal the
U.S. negotiates on Iran’s nuclear program.

Democrats in the Senate who have joined with Republicans on
a proposal to exert Congressional oversight of an Iran agreement
haven’t backed off even after the March 9 letter drew rebukes
from President Barack Obama and White House officials.

Tim Kaine, a Virginia Democrat who co-sponsored the
legislation with Tennessee Republican Bob Corker and others to
require congressional review of an Iran agreement, said he
remains “strongly supportive” of the bill even as he
criticized Republicans for injecting partisanship into the
debate and undercutting the negotiations.

“This had a lot of momentum in terms of getting bipartisan
sponsors,” he said in an interview. He called the letter a
stunt that had made some Democrats “more wary.”

While initial support is holding, the political rancor in
Washington now surrounding the Iran negotiations may complicate
the job of Corker, the Foreign Relations Committee chairman, as
he tries to cobble together enough Democratic votes to overcome
a sure veto of the legislation from Obama.

Republicans hold 54 seats in the Senate and 10 Democrats
have said they’ll support the measure, though only after the
end-of-the-month deadline for the current round of negotiations
among the U.S., five other world powers and Iran. That’s three
votes short of the number needed to override a veto.

Not Signing

Corker was one of seven Senate Republicans who didn’t sign
the letter.

“I didn’t view the letter as helping to achieve an outcome
that I would like to see, which is us having an opportunity to
appropriately weigh in on an arrangement that is so important to
our nation’s future and to the stability of the Middle East,”
Corker told reporters Tuesday.

Corker is one of the lead sponsors of the bill, which would
require congressional review of any deal with Iran and block the
administration from suspending congressional sanctions for 60
days. Sanctions would have to remain in place if Congress voted
a resolution disapproving the deal and then overrode an expected
presidential veto within the 60 days.

Given that there’s no agreement yet with Iran, it’s too
soon to know what Democrats will do, Anthony Cordesman, a
military analyst at the Center for Strategic and International
Studies in Washington, said in a phone interview.

“It’s one thing to oppose an agreement you haven’t seen,”
he said. “You can’t count the votes ’til the voting’s over.”

2016 Campaign

The Republican letter also has become part of the 2016
presidential campaign.

The four Senate Republicans considering a bid for the
party’s nomination in 2016 — Ted Cruz of Texas, Lindsey Graham
of South Carolina, Rand Paul of Kentucky and Marco Rubio of
Florida — all signed the letter. Former Texas Governor Rick
Perry and Louisiana Governor Bobby Jindal, also considering
presidential runs, added their names on Tuesday.

Former Secretary of State Hillary Clinton, a leading
contender for the Democratic nomination, called the letter “out
of step with the best traditions of American leadership.”

Republican Tom Cotton, the first-term senator who was the
driving force behind the letter, remained defiant Tuesday after
being accused by Obama and his allies of trying to undercut the
U.S. position in an international negotiation.

Obama’s Term

In the letter, the Republicans warned Iran’s leaders that
any deal with Obama might last only to the end of his term and
could be reversed by his successor or modified by Congress.

“We’re making sure that Iran’s leaders understand if
Congress doesn’t approve a deal, Congress won’t accept a deal,”
Cotton, 38, said Tuesday on MSNBC’s “Morning Joe” program.
“Because we’re committing to stopping Iran from getting a
weapon.”

The administration has said that the agreement being
discussed would cut back Iran’s ability to enrich uranium and
ensure that Iran is a minimum of one-year from a breakout — the
time needed to assemble the fissile material for a weapon — for
at least 10 years. Obama has said any deal also would require
Iran to submit to a strict inspections regime.

For Cotton that’s not enough. He said Iran should have no
right to enrich uranium and the U.S. must keep a credible
military threat on the table to enforce the demands.

Peter Raven-Hansen, a national-security professor at George
Washington University Law School in Washington, said the
Republicans’ letter was clearly intended to influence the talks.

‘Extraordinary Departure’

“Now we have 47 people plus the president purporting to
speak for the United States,” Raven-Hansen said. “That really
is an extraordinary departure” from past practices.

He said it’s not unusual for presidents to make such
agreements and no matter what actions are taken by lawmakers,
“it may still be binding and in effect in international law.”

Cordesman said Congress has lots of options if it wants to
slow the process.

“If you want to make life living hell for everybody, there
is absolutely no doubt that both the Congress and administration
can do that,” he said. “The more the Congress presses, the
more the administration has to justify and explain.”

To contact the reporters on this story:
Toluse Olorunnipa in Washington at
tolorunnipa@bloomberg.net;
Kathleen Hunter in Washington at
khunter9@bloomberg.net

To contact the editors responsible for this story:
Joe Sobczyk at
jsobczyk@bloomberg.net;
Jodi Schneider at
jschneider50@bloomberg.net
Michael Shepard