Conservative groups are ramping up a campaign against Obamacare as the administration mounts a vigorous public outreach effort to bolster support for the law.

The Obama administration is spending hundreds of millions of dollars in a marketing campaign to educate people about the law and encourage eligible people to sign up for insurance, a campaign run directly out of the White House by top Obama aides using election-style targeting tactics. The White House is even appealing to Hollywood stars to help push the law.

Conservative groups are mounting their own counter-campaign on multiple fronts, appealing to the grassroots while also lobbying the legislative branch to cut funding for the health care overhaul officially known as the Affordable Care Act.

The campaigns come as President Barack Obama’s approval rating has fallen to its lowest level since 2011 and only 34 percent of Americans believe Obamacare to be good policy, according to a poll released Wednesday.

"I don’t think there’s an issue that has galvanized the conservative movement like this since cut, cap, and balance," said Andy Roth, vice president for government affairs at the Club for Growth, in reference to the Republican proposal for the budget during the 2011 debt ceiling debate.

At least one conservative group, Americans for Prosperity, spent over $1 million on TV advertisements in July. The conservative group’s ad came after the Obama-aligned dark-money group Organizing for Action, launched its own ads in June and July.

Multiple conservative groups, including Crossroads GPS, Heritage Action, and the Club for Growth, confirmed that they are planning public campaigns against Obamacare for the fall, although they would not divulge the details of their plans.

"Can’t give you details yet—there’s definitely more coming," Heritage Action’s Dan Holler said.

Crossroads GPS’ Jonathan Collegio said the group is looking at running TV ads highlighting the law’s flaws in order to push Congress to repeal the law "piece by piece," although he said that they are still working on the details.

Roth predicted that many groups will launch a strong push against the law come the August recess, when the members of Congress will return to their districts.

As of now, the groups are focusing on Congress and efforts there to delay and defund the law.

Conservative groups are working to support an effort to defund the administration’s ability to implement the law by attaching such a provision to the next continuing resolution, which funds the government. Sen. Mike Lee (R., Utah) is leading this effort in the Senate.

"We’ll be getting our activists engaged trying to whip people up to support the bill," Holler said. Both FreedomWorks’ vice president of healthcare policy Dean Clancy and the Club for Growth’s Roth said their groups are also strongly supporting this effort.

Such an effort could pass the House, although it would likely fail in the Senate, where Democrats hold a majority.

Holler was undeterred.

"Put the onus on the Senate, make Harry Reid explain why he wants to shut down the government to make sure he can fund Obamacare," he said.

Both conservatives and the administration are facing a time crunch, as the first major part of the law—the state-based health insurance exchanges—is set to roll out in just over two months on Oct. 1. Three months after that, people will begin receiving federal subsidies to help pay for insurance on the exchanges.

"Once these entitlements take root, it’s really hard to unwind after that," Holler said.

Defunding the law is the only way conservatives could touch one major weakness of the law at this point—the administration’s ability to implement effectively the exchanges.

"I just don’t see how the exchanges are going to be ready," said Sally Pipes, healthcare policy expert and president of the Pacific Research Institute.

However, the conservative groups’ campaigns could affect enrollment in the exchanges, should they be rolled out successfully—with potentially devastating consequences for the law’s main feature.

FreedomWorks is mounting a "Burn Your Obamacare Card" campaign to dissuade young voters from enrolling in the exchanges, likening Obamacare to the military draft.

"This is not a legislative effort," Clancy said. "It’s more of an educative effort to help young people especially understand that they are bearing the brunt of Obamacare’s costs. That’s why we liken it to a draft. … It’s a raw deal for a lot of people under 40 years old."

The success of the exchanges depends on the administration enrolling 7 million uninsured people—including 2.7 million between 18 and 35 years, known as the "young and healthy," said Pipes. Without these people enrolling, the pool of insured people paying premiums will be too small, and costs will consequently rise unsustainably.

FreedomWorks will be traveling to college campuses with the college group Young Americans for Liberty encouraging college students whom the law requires to buy insurance to pay the fine instead, Clancy said.

FreedomWorks is only spending a fraction of their $20 million budget on the campaign, Clancy said, highlighting the wide gap in resources available to conservatives and the administration and its allies.

Despite the disparity, Clancy was optimistic about conservatives’ chances at derailing the law, noting the rising premiums within the exchanges.

"We think it will be hard to get lots of people to sign up," he said.