BOSTON -- With Election Day less than four weeks away, the gubernatorial candidates have staked out clear differences on issues ranging from bilingual education to the death penalty to welfare-to-work requirements.

But voters may have trouble distinguishing between the leading candidates, Democrat Shannon O'Brien and Republican Mitt Romney, on key issues such as the MCAS test and abortion, on which they are pushing similar policy proposals.

Bilingual education has been a focus of the campaign, largely because an initiative headed for the ballot would dismantle the state's 30-year-old bilingual education program and replace it with a one-year, English immersion program.

Romney, the former Winter Olympic chief, supports English immersion because he says it helps children integrate faster and find good jobs. O'Brien, the state treasurer, opposes it because she says it goes too far by forcing schools to use a single method of teaching English.

The issue sparked a lively exchange during Wednesday's gubernatorial debate, in which Green Party candidate Jill Stein disputed Romney's assertion that in California, where English immersion is already the law, students are succeeding at learning English more quickly.

Stein, independent Barbara Johnson and Libertarian Carla Howell all oppose the ballot question's English immersion program.

The death penalty is another divisive issue. Romney and Johnson support use of the death penalty in cases such as terrorism, the murder of witnesses, and violence against children where there is "incontrovertible" evidence.

O'Brien, Stein and Howell oppose the death penalty, citing the possibility the wrong person could be convicted and killed. O'Brien and Stein said the death penalty has been applied disproportionately to blacks and Latinos.

Jerold Duquette, a political science professor from Springfield, said issues often have little impact on voters. People always intend to vote based on issues but instead focus on the candidates' honesty, integrity, independence and character, he said.

In the current race, O'Brien is trying to tout her integrity and experience, while Romney is pushing his independence, said Duquette, who teaches at Central Connecticut State University.

"What they are are values that the candidates have twisted into issues," he said. That can lead to difficulty once the person is elected.

"If I've spent my entire campaign convincing you that I'm honest and my opponent isn't honest, what do you know about what I'm going to do? Not a damn thing," Duquette said.

O'Brien and Romney, the two leading candidates, share similar views on two issues important to many voters: Abortion and the MCAS exam.

Both candidates say as governor they would strongly uphold laws that protect abortion rights, even though O'Brien opposed abortion while in the Legislature 15 years ago except in cases of rape, incest or a threat to the mother's health, and Romney says he is personally opposed to it.

Last week, the two candidates sparred over who was the strongest abortion rights supporter, with each touting endorsements from abortion rights groups and challenging each other's records on the issue.

Stein and Howell support abortion rights, while Johnson appeared to hold the most conservative view on the issue: She said she supports it only in cases of rape, incest or when the mother's health is threatened.

The MCAS test -- officially known as the Massachusetts Comprehensive Assessment System test -- looms large for the next governor. In June, seniors for the first time will need a passing grade to get a diploma. About 12,000 of this year's 64,000 seniors have so far failed to do so.

But unlike in the Democratic primary, when two candidates supported the test and two opposed it, O'Brien and Romney both support the test as a graduation requirement. They say it is necessary to improve education and make sure the billions of dollars in education funding in the last decade are well spent.

Stein, Howell and Johnson all oppose using the test as a graduation requirement. They say it forces students to prepare for the test, but detracts from free thinking.

"It's the state government's version of trivial pursuit: an unrelated collection of facts and figures that make a mockery of education," Howell said.

On the current requirement that Massachusetts welfare recipients work 20 hours to be eligible for benefits, Romney said it is working well and should be preserved. O'Brien, Stein and Johnson said education and training should qualify towards the 20-hour requirement.

Howell, who would replace all government welfare with private charity, favors neither. (AP)