How much say Congress has on a possible nuclear deal with Iran will be tested Tuesday as a controversial bill goes up for a vote in the Senate Foreign Relations committee.
The Obama administration has been very critical of legislation that would give Congress a final say in approving or rejecting a deal.
In an interview with The New York Times, Obama said the newly agreed on framework of a nuclear deal with Iran represents a “once in a lifetime opportunity” to prevent Tehran from getting a nuclear weapon and to move toward stabilizing the Middle East.
On Monday, the administration stepped up its lobbying campaign on Capitol Hill.
"The way the legislation is currently written is something that we strongly oppose," White House press secretary Josh Earnest said. "But, again, we continue to have extensive conversations with members of Congress on Capitol Hill."
Secretary of State John Kerry postponed a foreign trip to meet with members of the House to discuss the negotiations. Kerry, Energy Secretary Ernest Moniz, Treasury Secretary Jack Lew and senior officials in the intelligence community were holding classified briefings Monday and Tuesday with members of the House and Senate.
Earnest said some Republicans are "rigidly partisan" and will reject any deal just because Obama supports it. He said that while there is some Democratic opposition, administration officials will continue to talk with members of his party. So far, the president and other senior administration officials have made more than 130 telephone calls to members of Congress to discuss the negotiations.
"I think there are some Democrats who will listen to this pitch," Earnest said. "I don't know if it will convince them all, but there is a strong case to make and it's one that we intend to continue making."
At the White House, Obama met with Jewish leaders. While Israeli Prime Minister Benjamin Netanyahu is intensely skeptical that international negotiators can reach a verifiable deal with Iran, which has threatened to destroy Israel, some American Jewish groups have backed the international negotiations.
Rep. Kevin McCarthy, R-Calif., told reporters that he spoke with Sen. Bob Corker, R-Tenn., chairman of the Senate Foreign Relations Committee, earlier in the day. McCarthy said he told Corker that if the Senate approves the bill, the House will vote on it.
"It's my intention to bring it to the floor of the House and move it," McCarthy said at a news conference as Congress was returning from a two-week spring break.
Republicans and Democrats maintain that Congress should have a say on an international deal with Tehran to curb its nuclear program and have lined up behind legislation. The White House has pushed back, threatening a presidential veto while warning that the bill could scuttle the delicate talks involving the United States, Iran and five world powers.
"Lines in the sands have moved back," McCarthy said, claiming the U.S. has back-tracked on some of the demands it had at the beginning of the talks. "A lot of the questions will be why have they moved back and will Iran ever be able to have the capability of having a nuclear weapon? That's a key question."
Under the bill, Obama could unilaterally lift or ease any sanctions that were imposed on Iran through presidential executive means. But the bill would prohibit him for 60 days from suspending, waiving or otherwise easing any sanctions that Congress levied on Iran. During that 60-day period, Congress could hold hearings and approve, disapprove or take no action on any final nuclear agreement with Iran.
If Congress passed a joint resolution approving a final deal -- or took no action -- Obama could move ahead to ease sanctions levied by Congress. But if Congress passed a joint resolution disapproving it, Obama would be blocked from providing Iran with any relief from congressional sanctions.
Iran says its program is for civilian purposes, but the U.S. and its partners negotiating with Tehran suspect Tehran is keen to become a nuclear-armed powerhouse in the Middle East, where it already holds much sway.
The bill has led to a political tug of war on Capitol Hill, with Republicans trying to raise the bar so high that a final deal might be impossible, and Democrats aiming to give the White House more room to negotiate with Tehran.
Senators of both parties are considering more than 50 amendments to the measure introduced by Corker and Sen. Bob Menendez, D-N.J.
The Associated Press contributed to this report.