And they thought passage was the hard part.

Almost a year after Democratic leaders and a coalition of business, local government and labor interests lobbied furiously to get a massive road-repair bill through the state Legislature, the same alliance is ready to defend a 12-cent-per-gallon increase in California’s gas tax that’s key to the bill’s aim of raising more than $50 billion over 10 years.

Signature-gathering is underway for a ballot measure that would repeal the gas tax hike and other revenue-boosters in the bill, known as SB 1 or the Road Repair and Accountability Act of 2017. Organizers say they’ve already collected more than 450,000 registered voters’ signatures toward the 584,407-signature requirement needed to get the measure on the November ballot.

Should that happen, SB 1’s defenders hope to convince voters that in the long haul, a repeal would cost them more than leaving the bill in place.

Gov. Jerry Brown defended the gas tax hike in his final State of the State address Jan. 25.

“Fighting a gas tax may appear to be good politics, but it isn’t,” Brown said. “I will do everything in my power to defeat any repeal effort that may make it to the ballot.”

SB 1 was the focus of an intense lobbying campaign by Brown and other top Democrats, who saw the bill as the best way to tackle a road-repair backlog of at least $137 billion and to fund new transportation infrastructure.

It passed last April — though every Republican save for one state senator voted no and it barely cleared the two-thirds supermajority requirement to approve tax increases.

Besides raising the gas tax last November, SB 1 imposed new annual fees on vehicles and raised the state’s diesel tax.

‘A big fraud’

The repeal measure would do away with the tax hikes and fees and would require voter approval for any future gas tax increase. It’s being led by former San Diego councilman and conservative talk show host Carl DeMaio.

GOP candidate for governor and San Diego businessman John Cox pledged a “significant” amount of money to get the measure on the ballot. With the possibility that the GOP might be shut out of the November elections for governor and U.S. Senate — California’s primary advances the top two vote-getters, regardless of party — a gas tax repeal could be a lure to boost California Republican voter turnout.

There used to be two repeal efforts. But a push led by Republican Assemblyman Travis Allen of Orange County, who also is running for governor, faltered.

The effort led by DeMaio is forging ahead. Events like a $1.99-a-gallon gas sale at an Indio service station have helped gather signatures in a state where a recent poll of likely voters showed 52 percent in favor of repealing the tax increase.

“Things are going great – way, way ahead of schedule,” DeMaio said in a recent phone interview.

Organizers have until May 21 to submit signatures, but DeMaio said the plan is to submit them ahead of the deadline with more signatures than what’s required so there is breathing room in case some signatures are invalidated.

The repeal effort’s message is straightforward – Californians pay among the highest gas prices in the nation, the state already has enough money to fix roads and Sacramento can’t be trusted with more taxpayer dollars.

“We expect (gas tax increase supporters are) going to lie through their teeth,” DeMaio said. “They’ve always seen this as a way to finance their pet projects. I have faith in the voters. I think the voters of California understand this has been a big fraud.”

‘Already working for you’

SB 1’s backers say it’s the other side that’s spreading misinformation. Michael Quigley, executive director of the Fix Our Roads Coalition, noted that voters in June will have the chance to approve a state constitutional amendment restricting money from the new vehicle fees and the diesel tax hike to transportation spending.

It’s a historically Republican principle to pay for transportation with a dedicated revenue stream, said Quigley, whose coalition, which backed SB 1, consists of labor groups as well as agencies representing local governments and business and construction interests.

“(Opponents’) proposals would make things worse,” he said. “They don’t offer any alternatives … We want to move forward with a historical funding source (for transportation).”

He added: “The focus should be on protecting the revenue we do have and provide value to taxpayers in terms of transportation infrastructure.”

If passed, the repeal measure would cost the state $2.9 billion in 2018-19 and $4.9 billion by 2020-21, according to a state analysis. Projects funded or accelerated by SB 1 are already being announced, and the coalition’s website lets users see how SB 1 money is being spent in their community.

“As far as right now is concerned, all of these new gas taxes are already working for you,” said Lucy Dunn, a state transportation commission member and president and CEO of the Orange County Business Council.

As for the idea that the state has enough money for road repairs without SB 1, Dunn said that’s not the case, since much of the state’s tax revenue is restricted to specific uses.

“Should this be repealed, literally traffic improvement projects, those bulldozers, that equipment will be stopped dead on the roads,” she said. “Every single district in California is benefiting from this.”

Gas tax fight

Here’s where you can learn more about the arguments for and against repealing California’s recent gas-tax increase.

Pro-repeal: www.givevotersavoice.com. Signature petitions can be downloaded at this website.

Anti-repeal: www.fixcaroads.com. The website has information on how SB 1 money will be spent in your community.

State website: rebuildingca.ca.gov contains more information on SB 1.