David Trone, candidate for Maryland’s 6th Congressional District, talks with election judges on June 26 in Frederick, Md. (Bill Green/The Frederick News-Post via AP)

DAVID TRONE, the wine and liquor retailing magnate making his second run for Congress in Maryland, has a credible claim to the title of Most Improved Candidate, at least in the Washington region. Having impressed with his business acumen, but less so his policy chops, during his first race — in the 2016 Democratic primary in the state’s 8th District, which he lost — Mr. Trone, a Democrat, now running in the 6th District, has formidable command of an array of issues in a sprawling district that includes a chunk of suburban Montgomery County and stretches to the West Virginia border. Detail-oriented, studious and no-nonsense, he would be an excellent successor to Rep. John Delaney (D), the three-term incumbent who is bowing out to run for president.

By contrast, the Republican candidate, Amie Hoeber, a defense consultant also seeking a seat for a second time, dismissed Montgomery County, where she and a big chunk of the district’s constituents live. “There’s 59 percent of the rest of the district that I care about,” she said, referring to the district’s western, GOP-leaning portions, some of which are closer to Ohio than to Washington. She is lightly informed on a range of issues — for example, freely admitting to knowing little about federal funding for Metro, which is vital to constituents whom she aspires to represent. (Some 37,000 daily Metrorail commuters live in Zip codes fully or partially within the 6th District, according to Metro.)

We support Mr. Trone, who has the makings of a serious, substantive and responsive member of Congress.

Mr. Trone makes an intelligent critique of the tax bill enacted last year by Congress, which he correctly calls a massive, unwarranted gift to the wealthiest Americans, himself included. (Ms. Hoeber is also well off; both candidates, as well as Ms. Hoeber’s husband, have spent heavily on their campaigns.) Mr. Trone rightly worries that its effect is to explode the federal deficit and long-term debt, “all for the benefit of my income bracket, which didn’t need any help.”

He’d prefer to devote more federal funding to the National Institutes of Health for research on medicine and disease, and on the opioid epidemic, which has hit hard in Maryland. To pay for those priorities, he favors imposing a minimum tax of 30 percent on millionaires — the so-called Buffett rule, named for billionaire investor Warren Buffett — and by closing the loophole on so-called carried interest, which benefits wealthy Wall Street financiers.

Ms. Hoeber’s policy positions are a muddle. She claims expertise in national security and foreign affairs, based on her business background and a position in the Pentagon more than 30 years ago. But she blithely explained her support for the U.S. withdrawal from the Trans-Pacific Partnership by citing China’s “great influence” in the trade agreement. In fact, it was crafted largely as a counterweight to Chinese economic power.

Similarly, Ms. Hoeber says she would increase federal spending on roads but has given no thought to where the money would come from. When pressed, she said she would divert it from federal education funds, shifting the burden of paying for schools to states and localities — which would be an unwelcome surprise for Maryland Gov. Larry Hogan (R) and taxpayers in the counties that comprise the 6th District.

The best choice, by a mile, is Mr. Trone.