Lt. Gov. Anthony Brown kicks off his campaign for governor in May. (Photo by Astrid Riecken For The Washington Post)

Lt. Gov. Anthony G. Brown (D) on Tuesday will propose making pre-kindergarten education available by 2018 to any Maryland family that wants to enroll their 4-year-old, according to a draft of his plan provided by his gubernatorial campaign.

The estimated cost to the state — about $138 million a year — would likely be covered by proceeds from Maryland’s gambling program, according to Brown aides.

The initiative is the first in what the Brown campaign said will be a steady rollout of policy proposals leading up to next year’s election. Brown faces at least two Democrats, Attorney General Douglas F. Gansler and Del. Heather R. Mizeur (Montgomery) in the June primary.

Gansler voiced a similar goal in a speech last week — pledging to fund full-day pre-K for disadvantaged families — but did not offer the same specifics or timetable that Brown lays out in his plan. The Brown plan is scheduled to be formally unveiled at a press conference Tuesday afternoon in Baltimore.

“While the benefits of pre-kindergarten education are well known, too many families do not have access to quality, affordable pre-K,” Brown says in the draft of his plan. “The #1 school system in the nation can and should do better.”

In broad terms, Brown is seeking to phase in the availability of “universal” pre-K, building on efforts already in place to help lower-income families get access. Interested families initially would be guaranteed access to at least half-day programs. By 2022, full-day programs would be available to all families, increasing the cost of the initiative by an unspecified amount.

The rollout of Brown’s plan marks a new phase in his campaign for governor, which he launched in May.

To this point, Brown’s public events have focused on endorsements he has claimed from fellow Democrats and interest groups.

Gansler has sought to draw a contrast with his chief Democratic rival by holding a series of events focused on policy ideas, on issues such as expanding manufacturing and creating greater “transparency” in government.

In his speech last week, Gansler also proposed using gambling proceeds to pay for the cost of pre-K programs.

Both candidates are banking on the success of the state’s casinos. Last year, Maryland voters authorized a sixth casino, to be located in Prince George’s County, and the legalization of table games, such as black jack and roulette, at the state’s previously slots-only venues.

The largest share of casino revenue is currently earmarked for K-12 public education.