Maryland Gov. Larry Hogan (R), left, and Democratic gubernatorial nominee Ben Jealous. (Pete Marovich/AP/For The Post/AP)

MARYLAND GOV. Larry Hogan owes something of his popularity to his penchant for centrism, caution and political small ball — a shrewd strategy for a Republican chief executive in a heavily Democratic state. That, plus a winning personality deployed publicly when he grappled with cancer soon after taking office, has given Mr. Hogan enviable poll ratings and a solid shot of reelection to a second term in this fall’s elections.

Mr. Hogan’s Democratic opponent, Ben Jealous, is anything but a cautious small-baller, let alone a centrist one. A former head of the NAACP, Mr. Jealous, riding his party’s tilt to the left, has advanced a blueprint of proposals so ambitious, and so potentially costly, that GOP attack ads are already asserting that enacting even a portion of it would bust Maryland’s budget.

It’s a cliche to say that a political contest offers voters a stark choice, but this race is an unambiguous study in contrasts.

Mr. Hogan’s first three years in office have been as notable for what he didn’t do as for what he did. Unlike most other Republican governors, he did not embrace President Trump; in fact, he distanced himself at almost every opportunity, most recently by declining to support the nomination of Judge Brett M. Kavanaugh to the Supreme Court. He did not dwell on culturally divisive social issues such as abortion and gun control; to the contrary, he signed gun-control measures backed by Democrats. And, despite having denounced his Democratic predecessor, Martin O’Malley, for raising taxes, he did not unleash a tax-cutting spree of the sort that proved ruinous for GOP governors in Kansas and Louisiana. He supported a new transit line for the Maryland suburbs.

Mr. Hogan has combined crowd-pleasing measures such as delaying the start date of public schools with signing on to Democratic legislative measures — often without acknowledging the original authors — while asserting his bipartisan bona fides. Given the governor’s incrementalism and lack of any signature marquee initiative, his challenge is to convince Marylanders that he has a vision for the state.

By contrast, there’s little question that Mr. Jealous has an agenda and a vision. The question is whether it’s implementable, wise or remotely bipartisan.

He would embrace a single-payer health-care system, under which the state would pay nearly all medical bills, an experiment that proved unaffordable before it could be tried in Vermont. He would raise pay for teachers by 29 percent; make higher education at public colleges debt-free; and provide universal prekindergarten. (And that’s a highly abbreviated list of the pricey programs Mr. Jealous supports.) To pay for it all, Mr. Jealous would soak the rich — read: Montgomery County — by raising taxes on the top 1 percent of taxpayers; legalize and tax marijuana; and slash spending on roads (by building fewer of them) and prisons (by overhauling the criminal-justice system).

Mr. Hogan has governed as a centrist. Mr. Jealous is an unapologetic liberal. Those crisp battle lines will present Marylanders with a clear-cut decision.