Democrat David Garcia, an education professor who lost to Diane Douglas in the 2014 race for school superintendent, is expected to announce next week that he's running for governor in 2018, according to people familiar with his plans.

For the last several months, Garcia had been weighing whether to run again for superintendent, jump into the campaign for governor or just sit on the sidelines.

Thursday's passage of a sweeping expansion of Arizona's school-voucher program appeared to give Garcia the issue he needed to propel a campaign for governor.

He posted this tweet Friday hinting at his plans:

Garcia would be the first Democrat to formally enter the race. State Sen. Steve Farley of Tucson has said he is considering a run.

Any Democrat would face a formidable opponent in Republican incumbent Doug Ducey, who has presided over a period of economic growth, has twice won statewide elections and has access to millions of dollars in campaign cash.

Also, Republicans typically hold a larger turnout advantage in off-year elections than during presidential years.

But Democrats believe Ducey forfeited his claim to be the "education governor" this week with the school-voucher expansion.

The governor twisted arms behind the scenes to pass legislation that many education advocates view as an assault on public schools.

Since last year's campaign for Prop 123, education issues have energized the Democratic base.

Garcia's defeat in 2014 shocked Democrats. Douglas was widely viewed as a weak candidate, but Garcia underperformed in Democrat-rich Pima County.

Political analysts suggested that many voters had trouble casting a ballot for a Latino candidate. A Latino has not won statewide office in Arizona since Raul Castro took the governor's race in 1974.

Ducey has not yet announced his plans for 2018 but is widely expected to run for re-election.