File photo of White House.
The White House dispatched Vice President Joe Biden to Congress for a second straight day Thursday in a bid to soothe skepticism about the historic nuclear deal with Iran, but Democrats remained wary.
The veteran former senator sought to assuage concerns expressed by some of his onetime colleagues with detailed explanations about the international inspections regime and other controversial elements of the accord.
"He made a good case. He did not launch into a major defense (of the deal), instead he answered questions," Senator Tim Kaine said after Biden met with Democrats on the Senate Foreign Relations Committee.
"He allayed some concerns," Kaine added, while declining to say whether he was committed to supporting the pact.
A day earlier Biden met with Democrats in the House of Representatives on a similar mission.
Republican House Speaker John Boehner reiterated his concerns about the agreement Thursday.
"Given everything I've seen so far, this is a bad deal. It paves the way for a nuclear Iran," he said.
"We're going to fight a bad deal that's wrong for our national security and wrong for the country."
The accord sees Iran's nuclear program curtailed in exchange for an easing of crippling economic sanctions.
Congress has 60 days to review the agreement, and can vote to approve or reject it.
Under legislation passed in May, President Barack Obama is barred from lifting congressional sanctions on Iran during the review period, unless Congress approves the deal during that time.
Many Republicans, including several running for president in 2016, have already expressed opposition to it.
Democrats, while admittedly unsure, are urging colleagues to study the agreement and consider experts' testimony before passing judgment.
Should Congress pass a resolution of disapproval, Obama would veto it.
Two-thirds of lawmakers would be needed to override a presidential veto, and top House Democrat Nancy Pelosi expressed confidence Thursday that her caucus would prevent such an override.
"I'm very optimistic about our ability to support the president," she said.
Another phase in Obama's full-court press begins next week, when Secretary of State John Kerry, who was instrumental in striking this week's agreement with America's historic foe, testifies in the first of several congressional hearings on Iran.
Energy Secretary Ernest Moniz and Treasury Secretary Jack Lew will also testify.
Obama's judgment questionedComplicating the White House efforts on Capitol Hill, the United States introduced a draft resolution to the UN Security Council Wednesday seeking formal endorsement of the hard-won nuclear accord, a move that would allow lifting the web of international sanctions on Iran.
The diplomatic push left some US lawmakers flabbergasted because it presses for United Nations action before Congress has had its chance to weigh in.
Republican Bob Corker, the Senate Foreign Relations Committee chairman, unleashed withering criticism of Obama for the move.
"I question the judgment of our president and the other members," Corker told reporters, presumably speaking about the members of the Security Council including Russia and China.
"They're going to be agreeing to an agreement that they don't even know they can implement," Corker said.
The top Democrat on the panel, Senator Ben Cardin, agreed that the UN move amounted to jumping the gun.
"I don't think the United States should pursue this until after we've done the 60-day review," Cardin said.
Kerry is scheduled to testify July 23 before Corker's panel.
House Foreign Affairs Committee chairman Ed Royce said he wanted to hold hearings with Kerry "as soon as possible," although no schedule has been released.