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Story highlights

Republicans and Democrats alike have expressed doubt the plan would be received warmly on Capitol Hill

The high bar for action on Capitol Hill will make it difficult for opponents to block the President

(CNN) —  

With a historic deal meant to curb Iran’s nuclear ambitions in place, President Barack Obama has ticked off another legacy-making item on his checklist – as long as Congress doesn’t get in his way.

Early Tuesday, Obama launched a sales pitch to lawmakers who remain deeply skeptical of the nuclear deal. But while Congress retains the ability to nullify Obama’s accord with Tehran, the high bar for action on Capitol Hill – including building veto-proof majorities in just over two months – will make it difficult for opponents to block the President.

In its most simplistic form, the deal means that in exchange for limits on its nuclear activities, Iran would get relief from sanctions while being allowed to continue its atomic program for peaceful purposes. Many of the more technical points of the deal weren’t available Tuesday morning, and specifics could prove to be red flags for skeptical members of Congress, many of whom said they were still reviewing the specifics of the plan.

Congress has 60 days to review the deal, and if it opposes it can pass a resolution of disapproval to block its implementation. The administration now has five days to certify the agreement and formally present the deal to Capitol Hill. The clock on that 60 day period will not start until the official document is delivered to Capitol Hill.

The Republican controlled House has the votes to pass a resolution, but in the Senate Republicans would need to attract support from a half a dozen Democrats.

Because President Obama has already pledged to veto any bill to block the deal GOP leaders would need to convince enough Democrats to join with them to override his veto – a heavy lift. How the public views the deal will be critical, as Members of Congress will be back home for several weeks this summer before any vote.

RELATED: Landmark deal reached on Iran nuclear program

Obama vows to veto measure to block deal

While Obama on Tuesday said he welcomed a “robust” debate over the deal’s merits, he issued a warning to lawmakers considering blocking the agreement, bluntly threatening to veto any measure that would prevent the deal from going into effect.

“Precisely because the stakes are so high, this is not the time for politics,” he said in an address from the White House. “Tough talk from Washington does not solve problems. Hard nosed diplomacy, leadership that has united the world’s major powers, offers a more effective way of verifying Iran is not pursuing a nuclear weapon.”

Like the completion earlier this month of a diplomatic renewal with Cuba, the deal with Iran provides Obama a tentative foreign policy achievement in the final year-and-a-half of his presidency. Both are built on the premise of engaging traditional U.S. foes, a vow Obama made at the very beginning of his presidency when he declared to hostile nations the United States would “extend a hand if you are willing to unclench your fist.”

The deal – which was finalized after almost two years of talks – provides vindication for an administration that’s sought to emphasize diplomacy over military force.

“This deal demonstrates that American diplomacy can bring about real and meaningful change,” Obama said Tuesday, adding later that the deal “offers an opportunity to move in a new direction.”

But even Obama himself has admitted there are risks inherent in striking an accord with a sworn U.S. enemy. Lawmakers, many deeply wary of those risks, now have 60 days to digest the provisions included in the deal with Iran, a two-month review period Congress insisted upon as the negotiations unfolded.

Obama was initially resistant to any congressional review of the Iran pact. But faced with overwhelming support among lawmakers for some kind of evaluation period, the White House ultimately conceded that Congress could be able to review the final deal before it takes full effect.

It won’t be easy for Congress to inflict damage on the agreement. They must act quickly – and the two-month period in which they can scuttle the plan includes a month-long August recess, and only a handful of working days.

Foreign Relations Committee Chairman Bob Corker told reporters Monday he expects to start hearings sometime shortly after the 60-day clock begins – which will come sometime in the next five days, after the Director of National Intelligence completes a number of certifications to Congress about the deal, including that it meets U.S. non-proliferation objectives and does not jeopardize U.S. national security.

Corker said he wants first to ensure senators have ample time to read the agreement and its classified annexes so they are “well versed” before hearing from the administration and any outside experts he plans to call to testify.

Corker said he would like to complete hearings before the August recess – which begins Aug. 7 – so lawmakers have the recess to consider their positions. Under this scenario, up or down votes on the deal itself would not happen until mid-September, he said.

In the House, a similar process and timeframe is also expected.

Within the 60-day span, opponents of the measure must rally votes to either enact new sanctions against Iran, or to disallow Obama from easing sanctions as part of the deal, measures the President would veto.

Overriding the veto in Congress would require a two-thirds majority – meaning in the Senate, Obama must only secure a minimum of 34 votes in order for his deal to take effect. Additional time beyond the 60-day review period is included for Obama to veto any legislation, and for Congress to muster support for an override.

If lawmakers fail to pass any new restrictions during the review period – which ends in mid-September – the deal will go into place, and sanctions will be lifted in Iran.

But among deeply skeptical senators, who worry about Iran’s support for terror groups and incarceration of Americans, even 34 Democratic votes in support of Obama aren’t necessarily assured.

“Over this August recess there’s going to be fast-and-furious lobbying, and we don’t know whether there will be 34 votes,” said former Democratic Rep. Jane Harman, who now heads the Woodrow Wilson International Center for Scholars.

’A flawed perspective’

In the hours and days before the deal was announced, Republicans and Democrats alike expressed doubt the plan would be received warmly on Capitol Hill, where lawmakers have been voicing concern about Obama’s desire to lift sanctions on Iran for the entirety of the nearly two-year negotiations.

On Monday, the Obama administration claimed it was Republicans who would find themselves at a political disadvantage if they attempt a takedown of a deal that could end Iran’s nuclear program.

“When it comes to a tough sell, I think the tough sell is going to be on the part of Republicans if they try to tank the deal,” White House Press Secretary Josh Earnest said Monday.

But in the aftermath of the deal’s announcement, Republicans vowed a tough examination of the agreement.

“The comprehensive nuclear agreement announced today appears to further the flawed elements of April’s interim agreement because the Obama administration approached these talks from a flawed perspective: reaching the best deal acceptable to Iran, rather than actually advancing our national goal of ending Iran’s nuclear program,” Senate Majority Leader Mitch McConnell said in a statement.

Arkansas Sen. Tom Cotton, who, along with 46 Republican senators, authored a controversial open letter to Iranian leaders in March that warned them that a nuclear deal could be modified or abandoned by a future President, said the agreement was a “grievous, dangerous mistake.”

“It will give Iran tens of billions of dollars to finance (Iran’s) sponsorship of terrorism against the United States and our allies,” Cotton said in a statement. “It will lift embargoes on conventional weapons and ballistic-missile sales to Iran. And, ultimately, it will pave the way for Iran to obtain a nuclear weapon. If this deal is approved, it will represent a historic defeat for the United States.”

Corker, the Senate Foreign Relations Committee chairman, said in a statement that he begins “from a place of deep skepticism” as he prepares to read the agreement, adding that his committee “will conduct a rigorous review.”

New Jersey Sen. Robert Menendez, a senior member of the Senate Foreign Relations Committee, has led Democratic opposition to the administration’s Iran plans for months. On Tuesday, he told CNN’s Joe Johns that he was disappointed in what he said was the deal’s lack of “anytime, anywhere inspections,” which he “thought was something that was one of our red lines.” He added that the agreement still preserves Iran’s nuclear infrastructure but held out hope that “there can be an effort to get a better deal.”

“The bottom line is: The deal doesn’t end Iran’s nuclear program – it preserves it,” he said later in a statement.

Obama admits risks

But the potential for Iran to renege on its agreements isn’t a concern only of the plan’s opponents; Obama himself admitted there were risks to any deal in an interview earlier this year.

“Look, 20 years from now, I’m still going to be around, God willing. If Iran has a nuclear weapon, it’s my name on this,” he told The Atlantic’s Jeffrey Goldberg. “I think it’s fair to say that in addition to our profound national-security interests, I have a personal interest in locking this down.”

Obama’s stake in the Iran deal may only become more apparent after he leaves office; as in his diplomatic thaw with Cuba, the effects on ordinary citizens in those countries won’t be seen for several years.

He addressed the long-term prospects of success on Tuesday, saying the person who succeeds him in office – and even the president after that – will continue to enjoy the benefits of the deal.

“The same options available to me today will be available to any U.S. president in the future,” Obama said. “I have no doubt that 10 or 15 years from now, the person who holds this office will be in a far stronger position with Iran further away from a weapon.”

CNN’s Jethro Mullen, Nic Robertson, Deidre Walsh and Ted Barrett contributed to this report.