A tax to fund early childhood education and college readiness programs for Oakland students didn’t get the two-thirds vote in November usually required for special taxes to pass, but city officials now say, based on a recent legal opinion, a simple majority vote is good enough.

The Oakland City Council certified Measure AA on Friday evening, the first step toward enacting the parcel tax, even as council members acknowledged that doing so creates legal exposure for the city.

The measure’s opponents have vowed to sue.

The authority to move the education parcel tax forward comes from the San Francisco city attorney’s interpretation of a recent California Supreme Court decision. Dennis Herrera’s office last year said in a memo that citizen-initiated tax measures need only a simple majority to pass but government-driven ones still need a supermajority.

Certifying the measure allows the city to collect the taxes, even if it does not spend the money pending a legal ruling.

Measure AA would tax single-family homes at a rate of $198 a year and multiunit residences at $135. It was expected to generate $30 million in annual revenue and last for 30 years.

Most of the revenue would go toward early child-care and preschool programs, and another portion would fund college readiness programs, tuition assistance and efforts to fix racial inequities in access to higher education. The measure would also create a citizen commission to conduct oversight and audits.

The measure was championed by Schaaf and backed by Rep. Barbara Lee, D-Oakland; Assemblyman Rob Bonta, D-Alameda; the Oakland branch of the NAACP; the city’s SEIU Local 1021 and others.

The City Council, 6-1, certified the measure despite only 62 percent of voters approving it. Councilwoman Lynette Gibson McElhaney voted against certification, and Councilwoman Desley Brooks was absent.

The council is following the example set by San Francisco, which certified three tax measures that received a simple majority of voter support but did not reach the two-thirds threshold. Those measures, which would provide funding for homelessness programs, early childhood education and teacher raises, are already facing legal challenges.

The Oakland vote means City Attorney Barbara Parker will now file a “validation action” in court — essentially asking a judge to approve the city’s authority to certify the measure.

Shuwaski Young, campaign manager for “Yes on AA,” applauded the council’s move.

“It was brave and the right, moral thing to do for Oakland communities,” he said. “This gives way for an opportunity to really give low-income families an equal shot at quality education.”

Since the mid-1990s, ballot measures to raise taxes for specific purposes must get a two-thirds supermajority to pass. Taxes for the general fund need only a simple majority.

Sometimes, the distinction is blurred. Oakland’s soda tax was written as a general one, but supporters understood it would fund health programs. When Schaaf last year proposed using the money to help eliminate a budget deficit, she was lambasted by her colleagues on the council, and she quickly changed course.

The action by Oakland officials is “a misuse of power and the electoral process,” said Larry Tramutola, a political consultant for the “No on AA” campaign.

“This is a blatant power play by the proponents of this measure to use untested legal principles to move the measure forward when they didn’t get the two-thirds,” Tramutola said.

Angry homeowners charged that city officials were attempting to pass the measure without proper public noticing. An initial agenda item Tuesday about the election results included which initiatives passed and which ones failed but listed an ambiguous “passed/failed” next to Measure AA.

Marleen Sacks, an attorney who sued the city years ago over how a public safety parcel tax was being spent, wrote a letter to officials last week alleging violations of California open-meetings law. Afterward, the City Council brought the measure back on Friday.

Sacks and other opponents of the measure said that even if San Francisco’s analysis is right the Oakland initiative was not truly citizen-driven and instead written by an amalgam of public officials and union leaders.

Darien Shanske, a professor at UC Davis School of Law who specializes in state and local taxation, said that argument could be politically persuasive but not legally so.

But there remain “some tricky questions specific to Oakland,” Shanske said, given that Parker said in ballot materials the initiative needed two-thirds approval. That was unlike San Francisco’s contested Proposition C, which was advertised as only needing a simple majority.

“I think the San Francisco city attorney is correct and they will be vindicated, but it is an open question,” he said. “Ultimately, everyone is waiting to see what happens in the San Francisco litigation. If San Francisco wins, that’s going to be huge for California cities.”

Kimberly Veklerov is a San Francisco Chronicle staff writer. Email: kveklerov@sfchronicle.com Twitter: @kveklerov