Updated

The race to stop ObamaCare before Americans can officially sign up this fall for the government-backed health insurance intensified Sunday with two of the movement’s biggest champions confident they will succeed but acknowledging it will take a “tsunami” of support.

Texas Republican Sen. Ted Cruz, a Tea Party-backed lawmaker at the center of the effort to “defund” ObamaCare, said the fight will play out in the weeks before the Oct. 1 signup date and that success will require a grass-roots effort in which Americans across the country must “demand” their elected officials “do the right thing.”

“This fight is likely to heat up in the month of September,” Cruz told CNN’s “State of the Union." “That's going to be when the battle is engaged.”

Cruz is joining Heritage Action for America, the advocacy arm of the conservative Heritage Foundation think tank, to get lawmakers after they return to Capitol Hill next week to separate out ObamaCare from a temporary spending bill to keep the federal government running, then vote in favor of the spending bill to avoid a politically unpopular government shutdown.

However, he acknowledges Republicans still don’t have the support on Capitol Hill -- 41 members in the Senate or 218 in the House.

“We do not have the votes right now,” Cruz said. “But I believe if we see a grass-roots tsunami, that is going to cause Republicans and Democrats to listen to the people. … It is going to take a tsunami and I'm going to do everything I can to encourage that tsunami."

It will also take President Obama agreeing to defund his signature health reform law, which Cruz still thinks could happen.

Cruz, who joined the Heritage Action’s Defund ObamaCare Town Hall Tour last week in Dallas, repeated the argument that the law is a jobs killer because of the financial burden it puts on businesses.

And he proposes a multi-pronged reform of the country’s health-care system that includes allowing Americans to purchase health insurance from any state and expanding health savings accounts “to make it easier in a tax-advantage way to take care of prevention and routine medical needs.”

Cruz, who appears to be interested in a 2016 presidential run, was joined on the show by Democratic politician and medical doctor Howard Dean, who seems to have publicly re-emerged ahead of the 2016 presidential elections.

Dean, a former Vermont governor and 2004 Democratic presidential candidate, called Cruz “a slick spokesman.”

“God help us if he gets to be anything more than the senator from Texas,” Dean added.

Former South Carolina Republican Sen. Jim DeMint, who left Congress this year to become president of the Heritage Foundation, told CNN that ObamaCare was passed under false pretenses, in light of recent revelations about costs and requirements.

“American people were lied to, and they have every right to demand that their representatives stop this unfair and un-American law,” he said.