Congressional opponents of the nuclear deal with Iran are using words like “horrible,” “disgrace” and “disturbed” to describe the agreement, signaling the tough fight ahead as lawmakers impart on a 60-day review period.

At a monthly gathering of House conservatives on Capitol Hill, skeptical lawmakers said they hoped the review period—which will overlap with Congress’ August recess—will help them lobby the public against the deal.

“I think you will see an unprecedented amount of person-to-person, member-to-member discussions and efforts … to persuade people who are undecided and encourage them to oppose this deal,” said Rep. Cynthia Lummis, R-Wyo.

“This will be an opportunity for members to approach members, in a sincerely, objective, non-partisan way to persuade each other to how ill advised this is, and to say, please let’s work together as members of the legislative branch and override this veto.”

The nuclear deal, negotiated by Iran and six world powers led by the U.S., limits Tehran’s nuclear ability for more than a decade in return for lifting international oil and financial sanctions.

Iranians celebrate the nuclear agreement in Tehran on Tuesday. Under the deal, the Iranian government will be relieved of sanctions. (Photo: Chine Nouvelle/SIPA/Newscom)

Iranians celebrate the nuclear agreement in Tehran on Tuesday. Under the deal, the Iranian government will be relieved of sanctions. (Photo: Chine Nouvelle/SIPA/Newscom)

Under the mechanism approved by Congress, it will be very difficult for lawmakers to overturn the deal.

Congress will have 60 days to review the deal before legislators will vote to accept or reject it—or do nothing. But the president can veto any resolution of disapproval. Congress needs a two-thirds majority in each house to override the veto.

To sustain the veto, the White House can lose no more than 12 senators from the 46-member caucus.

In trying to stoke Democrats against the agreement, conservatives invoked Israel’s skepticism that Iran will fulfill the terms of the deal.

“It’s a bad deal,” said Rep. Jim Jordan, R-Ohio, who chairs the conservative House Freedom Caucus.

“There’s a whole host of reasons why I think it’s bad. When you have Israel and all the Arab nations agreeing it’s bad that should tell us something.”

Though many of the lawmakers say they haven’t yet read the deal, some oppose the entire idea of negotiating with an Iranian regime that funds terrorism across the Middle East and holds Americans hostage.

“When they claim they want to be a part of community of nations, that they want to have constructive engagement in world, and they are unwilling to release these political prisoners, I don’t know why we are making any agreements with them,” said Rep. Raul Labrador, R-Idaho.

“I am very disturbed without even looking at the agreement and sure will be more disturbed after reading it.”

Meanwhile, in a press conference today, President Obama urged Congress to approve the deal, calling it “an opportunity that may not come again in our lifetimes.”

Obama argues that there’s no other credible alternative to contain Iran’s nuclear program, and that “99 percent of the world community and majority of nuclear experts” say the deal “will prevent Iran from a nuclear bomb.”

“If the alternative is that we should bring Iran to heel through military force, they should say so,” Obama said of critics.

President Obama exits a press conference Wednesday where he urged Congress to evaluate the nuclear deal "based on facts." (Photo: Michael Reynolds/EPA/Newscom)

President Obama exits a press conference Wednesday where he urged Congress to evaluate the nuclear deal “based on facts.” (Photo: Michael Reynolds/EPA/Newscom)

The president also defended some of the main criticisms of the deal, including the fact that Iran would have to be notified 24 days in advance before inspectors can gain access to nuclear sites they are suspicious of.

“This isn’t something you put in a closet,” Obama said of nuclear infrastructure. “This isn’t something you put on a dolly and wheel off somewhere.”

Obama made clear that he does not view the nuclear deal as the first step in a wider opening of diplomatic ties with Iran.

He also strongly countered those who say that the deal fails to address Iran’s support for terrorism and Tehran’s imprisonment of Americans.

“The notion that I am content, that I celebrate with American citizens languishing in Iranian jails, [is] nonsense,” Obama said, arguing that attaching the hostage issue to the deal would encourage Iran to take Americans captive in the future.

With Obama’s presidential power, and the difficulty in overriding a congressional veto of the deal, dubious lawmakers are skeptical they can do anything to stop it.

“The game is rigged in favor of getting this thing done,” Jordan said. “[Obama] said Congress should weigh in on this. Well heck yeah they should weigh in—he wants them to weigh in because he knows it’s going to take 67 members of the Senate to disapprove it.”

Regardless of the odds, opponents say they will do their best to take advantage of the lengthy review period.

“I challenge the American people to make this the issue of the August recess,” said Rep. Paul Gosar, R-Ariz.

“It’s time to pepper your senators and hold them accountable, whether they are Republican or Democrat … to take us to task and ask us for validation—to explain the deal, to explain why we even went into the deal. I challenge the American people: We can do this, and we need your help.”