Kathleen Matthews in Rockville on Jan. 18. (Kate Patterson/For The Washington Post)

A TALENTED roster of candidates is on the Democratic primary ballot in Maryland’s 8th Congressional District, a safe Democratic seat that the highly able incumbent, Rep. Chris Van Hollen, is leaving to run for the Senate. The race, which seems likely to be the nation’s most expensive primary contest for a House seat, has it all: three state lawmakers, two former Obama administration officials and a rich businessman who is deluging the district’s airwaves with ads.

In this formidable lineup, one candidate stands out as having the potential to make an impact in Congress: Kathleen Matthews, a longtime TV journalist and, more recently, corporate executive. Ms. Matthews is a first-time candidate for elective office, but as a local reporter and anchor for WJLA for 25 years, and then as head of public affairs for Marriott International, she has developed a broad and deep facility with policy and politics. In the neighboring 6th District, which shares Montgomery County with the 8th, Rep. John Delaney, a two-term incumbent, has shown that a savvy newcomer with broad experience, including in business, can make a mark even from the minority in the GOP-dominated House. Ms. Matthews, whose progressive views are in tune with the district’s, would be in that mold of achiever.

Another strong candidate is Sen. Jamie Raskin, the Maryland Senate’s majority whip, who is recognized in Annapolis as an effective legislator. A constitutional law professor at American University, he played key roles in ending the death penalty, legalizing same-sex marriage and tightening gun control laws. He is respected in his legislative district, around Takoma Park, for granular attention to his constituents’ needs.

A third candidate has made a splash in the race due to his prodigious spending on campaign advertising: David Trone, co-owner of Total Wine & More, a large retailer. Mr. Trone, who, with his brother, built his business from scratch, has smarts and an inspiring personal story. But his scant experience in and knowledge of local, state and federal affairs, outside those directly affecting his business, is all too apparent.

Our preference for Ms. Matthews boils down to our belief that in Congress, she would be more pragmatic and less doctrinaire than the left-leaning Mr. Raskin, whose passionate liberalism is unsurpassed in Annapolis. Both candidates support gun control, clean energy, campaign finance reform and greater investment in education and health research. Ms. Matthews has greater potential, following the Van Hollen model, to move the ball forward in those areas. We endorse her in the April 26 primary.