Activists on both sides of the Iran nuclear deal are girding for an epic August recess showdown some predict could rival the game-changing 2009 late summer town hall battles over Obamacare.

Even before the House left for its August recess, groups on both sides of the Iran deal had begun their coordinated air and ground campaign focused on ratcheting up the pressure on Democrats to vote either for or against the deal when they return to Washington in September.

"This is Obamacare-level anger," said one senior official at an organization closely involved in the fight to vote down the Iran deal. "Iran is not just another foreign-policy issue. Americans remember that these are the guys that took [our citizens] hostage, killed our marines and blew apart the bodies of more than 500 U.S. soldiers in Iraq."

Democratic support is critical for the Obama administration ahead of the September vote in Congress to uphold or sink the deal. Republicans are expected to vote in near unison to oppose the accord, putting Democrats in the awkward position of sustaining an inevitable veto from President Obama or bucking him on what is set to become the most important part of his foreign policy legacy.

The president and his supporters are clearly worried about keeping Democrats in the fold over the August recess, and are furiously working with a whip team led by Minority Leader Nancy Pelosi in the House, as well as supporters such as the outside J Street group, which calls itself "the home for pro-Israel, pro-peace Americans," to keep the pressure on Democrats to back the deal.

On a conference call with Obama loyalists and liberal activist groups such as Americans United for Change Thursday night, the president put the August recess fight in dire terms.

"The stakes could not be higher … as big as the bully pulpit I have, it's not enough" when it comes to making the case for the Iran deal, he told supporters, according to a recording of the phone call obtained by the Washington Examiner, arguing that billionaire donors were pressuring members of Congress.

"I want everyone on the phone to get moving – do not wait," he said. "Right now the opponents of this deal have been flooding members of Congress and they're feeling it."

Obama said he's been meeting with lawmakers, who he said "don't really buy the arguments" against the deal.

"But I can feel when they start getting squishy … and you can counter-act that."

Most of the media attention so far has focused on AIPAC's deep-pocketed $20 million to $40 million TV ad campaign slamming the deal, but the group is also working with its national network of allies to mobilize an army of opponents to flood members' offices with phone calls and emails, show up at swing Democrats' town hall meetings and hold rallies across the country.

"We are engaged in a major bipartisan education and lobbying effort against the deal and for a better deal – this includes grassroots contacts with members of Congress, lobbying in Washington and support the efforts of Citizens for a Nuclear Free Iran," an AIPAC source told the Examiner.

Nuclear Free Iran is a 501(c)4 non-profit group with ties to AIPAC that lists several Democrats with long records of support for Israel on its advisory board, including former Sens. Evan Bayh of Indiana, Mark Begich of Alaska, Mary Landrieu of Louisiana and Joe Lieberman of Connecticut, who became an Independent before leaving the Senate in 2013.

AIPAC members, the source said, also will be meeting with their senators and representatives over the recess and attending town hall meetings held by members of Congress.

On Wednesday, the powerful lobbying group sent several hundreds of its members to meetings in more than 400 congressional offices, the source said.

Christians United for Israel, a nonprofit that boasts 2.1 million members nationwide, began its campaign by sending 5,000 members and supporters to Capitol Hill for its D.C. summit the Tuesday morning the administration announced it had reached a deal with Iran.

It has since worked to inundate members' offices with phone and email messages opposing the deal. After issuing an action alert urging calls to their congressmen to voice concern, the group's members sent more than 150,000 emails to congressional offices in a 24-hour period, according to Ari Morgenstern, the group's communications director.

The group plans to build on that effort over the recess and has identified more than 50 House Democrats and 20 senators to target by showing up to town hall meetings, and in some cases holding rallies in specific districts.

"The American people oppose this bad deal, and the more they learn about it, the more they oppose it," said David Brog, CUFI's executive director.

Brog says the group has two missions over the next month: to continue to educate its members about why the deal falls short and encourage them to educate their family and friends, and organize its members to set up meetings with elected officials and attend members' townhall meetings to raise the issue in person.

"There is nothing like a local outcry to make clear to members of Congress that they support this deal at their political peril," he said.

A pop-up advertisement on CUFI's website urges supporters to "Vote Against a Bad Iran Deal" and offers a one-click way to email senators and members of Congress asking them to vote against the deal.

A calendar of upcoming August events on the website lists two "Standing with Israel" events in Missouri in early August, and others in upstate New York, Ohio, Alabama, Pennsylvania and California.

But the group says they have members in every state and have more events and meetings with members of Congress planned in Wisconsin, Nebraska, Arizona and Virginia. For instance, for one meeting with an unnamed senator, the group plans to show up with 300 people opposed to the deal

"We fully expect the staff to be searching for a larger meeting room," Morgenstern said.

Democrats who think this is just another tough vote they have to get through, will be sadly mistaken, he stressed.

"All will not be forgotten – no member of Congress is going to be able to plead ignorance" when the flaws of the deal are exposed, he said.

"If the Iranians cheat, and we believe they will, and if this [deal] does not go as planned, then the member of Congress will be held to account," he said. "They are essentially putting the future of their seat in the hands of the Iranians."

Meanwhile, other anti-deal activist groups, such as the Israel Project, have commissioned a series of polls to roll out during the August recess to demonstrate growing opposition to the deal and push back against other surveys by proponents.

So far, there have been several major polls of Jewish Americans since the announcement of the nuclear deal showing conflicting results.

The Israel Project survey showed slightly more opposition to the deal than support for it with 47 percent against compared with 44 percent in favor and another commissioner by J Street, a major advocate for the deal, U.S. Jewish support is outpacing opposition by 20 percentage points – 60 to 40 percent.

Meanwhile, a CNN poll this week that did not limit itself to Jewish Americans, showed 52 percent of those surveyed saying Congress should kill the deal compared to 44 percent who want it approved.

Secure America Now, a conservative nonprofit group that focuses on U.S. foreign policy issues, also issued a poll this week finding support for the Iran nuclear deal declining.

The survey, released Wednesday, found that 45 percent of registered voters want lawmakers to oppose the agreement, an 8-percent spike from a month ago.