Maryland Democratic gubernatorial candidates Lt. Gov. Anthony Brown, left, Del. Heather Mizeur, center, and Attorney General Douglas F. Gansler, right. (Ricky Carioti/The Washington Post)

The three major Democratic candidates vying to be Maryland’s next governor share most of the same goals.

Lt. Gov. Anthony G. Brown, Attorney General Douglas F. Gansler and Del. Heather R. Mizeur (Montgomery) all consider themselves progressive Democrats. All three will tell you their priorities include creating jobs, improving schools and protecting the environment. And there is a lot of overlap in the dozens of policy proposals they have put forward during the campaign.

But over the course of a primary campaign that began more than a year ago — and that will end when voters go to the polls June 24 — some salient differences have emerged. Here’s a look at seven issues on which Brown, Gansler and Mizeur part ways.

Corporate income tax

Gansler wants to gradually reduce Maryland’s corporate income tax rate from 8.25 percent to 6 percent, to match the rate Virginia levies. His two rivals say the plan is misguided.

Under Gansler’s plan, the rate would drop by a quarter percentage point annually — meaning it would take nine years before it hit 6 percent. At that point, the state would collect at least $300 million less a year in corporate taxes than it does now, if current estimates by legislative analysts hold.

Brown and Mizeur argue that is too costly and say the state’s priority should be providing tax relief to small businesses, most of which don’t pay corporate taxes. Mizeur has issued a plan to do that.

Gansler says the cost of his tax cut would be offset by closing a loophole that allows international corporations to avoid paying taxes on Maryland operations.

Gansler also argues that by lowering the corporate tax rate, more businesses will come to Maryland and stay in the state.

And if that doesn’t happen as quickly as hoped, aides say, Gansler would consider slowing down the implementation of the rate reduction.

Personal income tax

Mizeur has proposed making personal income taxes more “progressive” by reducing what most Marylanders pay and increasing what higher-earners would owe. Mizeur says her plan would save 90 percent of Marylanders money — in the range of $50 to $150 a year.

Single filers earning $175,000 or more and joint filers making $250,000 or more could expect to pay more. But significant increases wouldn’t kick in until incomes reach $500,000 for single filers and $600,000 for joint filers, Mizeur aides say.

Brown says he will give the tax code a comprehensive look after taking office, and Gansler says too many taxes went up during the tenure of Gov. Martin O’Malley (D). But neither Brown nor Gansler has proposed specific plans to alter the personal income tax.

Legalizing marijuana

All three Democrats supported successful legislation this year to decriminalize possession of small amounts of marijuana. But they differ over whether Maryland should take the next step: legalization.

Mizeur has a plan to tax and regulate marijuana much the same way that Colorado and Washington state are doing. Legalization, she argues, would generate millions in new state revenue and help end a failed war on drugs.

Brown and Gansler both say such a step is premature and want to wait until more can be gleaned from the experiences of other states.

Expanding pre-kindergarten

Maryland currently provides free pre-K classes to nearly 29,000 children from economically disadvantaged families using a combination of state and federal funds.

All three Democrats favor getting more children enrolled, saying it is a way to reduce the achievement gap between those from poor families and those from wealthy ones.

But the candidates disagree over which families should be included in the expansion, along with how they would pay for the costs.

Mizeur wants to offer free, full-day pre-K to every 4-year-old, plus free half-day classes to 3-year-olds from families with incomes below a certain level. She says that this would cost around $280 million per year and that she would use new tax revenue from legalizing marijuana to pay for it.

Brown wants to offer free half-day or full-day classes to all 4-year-olds by 2018, which he estimates would cost as much as $138 million per year once fully implemented. Brown would fund the expansion with proceeds from casino gambling. By 2022, he hopes that all 4-year-olds will have access to full-day classes.

Gansler has proposed the most modest expansion: increasing half-day classes to full-day and then raising the family income limit to allow more children to enroll. Gansler expects that these changes would cost at least $20 million for the first year and could be paid for with gambling proceeds now earmarked for the horse-racing industry.

Pay raises for teachers

Gansler proposes boosting the salary of Maryland teachers — who make an average of $63,000 a year, he says — to $100,000 if they receive certification from the National Board for Professional Teaching Standards. Gansler reasons that more board-certified teachers will lead to bigger gains in student achievement. Neither Brown nor Mizeur is on board with that proposal.

Justin Schall, Brown’s campaign manager, said Brown thinks teachers should be supported, but he favors local control of salary decisions and supports the collective bargaining process. A Mizeur spokesman said she doesn’t support Gansler’s plan because research shows it won’t work.

Estate tax relief

The three Democrats differ over a bill passed this year that provides a break in estate taxes — and they differ over what to do about it now.

Maryland’s estate tax is imposed on the transfer of property valued above $1 million after someone dies. The bill that passed provides relief by gradually raising the $1 million exemption to match that of the federal government, which is $5.34 million this year (and scheduled to rise with inflation).

The break will eventually cost Maryland more than $130 million a year in tax revenue, according to legislative analysts.

Brown has said he would have stopped the bill from passing if he were governor. He thinks the state’s tax structure should be reviewed comprehensively instead of acted upon in a “piecemeal” fashion.

Mizeur calls the bill a “giveaway to millionaires” and says that as governor, she would seek to reverse.

Gansler said he was pleased with passage of the bill, which was supported by a strong majority of Democrats and Republicans.

State prosecutor’s office

As part of a larger plan to reduce government spending, Gansler proposes phasing out the Office of the Maryland State Prosecutor, which focuses on corruption among government officials and candidates for office.

Gansler called the office “a holdover from the Watergate era” and said the same cases could be pursued by other prosecutors on the local, state and federal levels. Eliminating the office could save $1.2 million a year, Gansler says.

Both Mizeur and Brown oppose the move. Brown said the office plays “an important role as an independent watchdog” and helps ensure voting rights and civil rights.