Maryland Gov. Larry Hogan (R). (Gail Burton/Associated Press)

MARYLAND GOV. Larry Hogan, a Republican in a heavily Democratic state, won election as a pro-business moderate, took office with a limited agenda and has governed from the center. For this, plus the sunny disposition he projected through a bout with cancer, Mr. Hogan has been rewarded with sky-high public approval ratings, which appear to have unhinged Democrats.

The latest eruption of the Democrats’ Hogan Derangement Syndrome occurred last week, when African American legislators accused him of racially motivated “assaults” on black communities. The so-called evidence included the governor’s decisions, last year, to kill a light-rail line, trim extra education funding and fund a new jail in Baltimore, while initially withholding funds for a new hospital in Prince George’s County. Both Baltimore City and Prince George’s are majority-black.

We didn’t support Mr. Hogan in his 2014 campaign. Nonetheless, what has been striking since he took office is neither his ideology (faint), nor his agenda (small-ball), nor his governing style (laid-back), nor his partisanship (run-of-the-mill) but the disproportionate attacks by Democrats on a governor whose record so far qualifies him as a moderate.

Last year they pilloried him for trying to divert money for the state’s underfunded pension system, a cause Democrats themselves embraced just four years earlier, before legislative amnesia set in. This year they derided his anodyne State of the State address, heavy on pledges to work collaboratively with Democrats, with initiatives — some targeted tax cuts and fee reductions; nonpartisan redistricting; efforts to combat heroin addiction — that could easily have been issued by a reform-minded Democrat.

Democrats responded with bills that would tilt the balance of power away from the governor and toward the Democrat-controlled legislature. Some of those measures, such as subjecting the state’s school superintendent to legislative approval, looked gratuitously political; amid criticism, it was essentially withdrawn Tuesday.

Despite the occasionally venomous rhetoric in Annapolis, neither Mr. Hogan nor the Democrats are playing for monumental stakes. Mr. Hogan’s Democratic predecessor, Martin O’Malley, managed to enact practically every big-ticket liberal policy Democrats could think of: same-sex marriage, gun control, tuition subsidies for illegal immigrants, ending the death penalty, and new taxes to finance higher spending on infrastructure and health care. Mr. Hogan has made no effort to roll those back, leaving Democrats to snipe at his small-bore attempts to trim spending.

When they have attacked him head-on, Mr. Hogan has sometimes simply yielded, as he did by restoring funds for the Prince George’s hospital and cutting them for a (badly needed) new jail in Baltimore. And while he rejected the light-rail Red Line in Baltimore, a project whose $2.9 billion price tag outstripped its likely benefits, he quickly proposed a less expensive program to improve the city’s bus service, which got high marks.

Before Mr. Hogan took office, Maryland was a virtual one-party state, led by a Republican governor for just four of the preceding 45 years. Now Democrats, encumbered by a sense of entitlement and baffled by a middle-of-the-road GOP governor, seem bereft of a strategy and grasping for an agenda. They would need both to wrest power from Mr. Hogan if, as expected, he seeks reelection in 2018.