Rep. Chris Van Hollen (D-Md.) at the second debate with Rep. Donna Edwards on March 18 in Greenbelt, Md. (Mark Gail/For The Washington Post)

THERE WAS a revealing moment last month in the first debate between Rep. Chris Van Hollen and Rep. Donna Edwards, the two main contenders in the high-stakes April 26 Democratic primary for U.S. Senate in Maryland, whose winner will be the heavy favorite to succeed retiring Sen. Barbara A. Mikulski. Mr. Van Hollen, respected on Capitol Hill for his legislative savvy, noted that Ms. Edwards had joined scores of conservative Republicans in Congress in opposing a 2011 budget accord that would have averted a catastrophic default on the federal debt, an event that would likely have sent the global economy into a tailspin.

Affecting incredulity, Ms. Edwards, one of the most liberal members of Congress, asked, “Does anybody really believe that I’m in the tea party?”

Well, no. But the question is more interesting than Ms. Edwards may have intended. For in opposing a tough deal that entailed deficit reduction, she did in fact join many ultra-conservative Republicans who believed the spending cuts weren’t adequate. Her politics may be the mirror image of the tea party’s, but Ms. Edwards has been equally hostile to pragmatic compromise.

Unlike Ms. Edwards, for whom bipartisan compromise on critical issues such as deficit reduction is apostasy, Mr. Van Hollen is one of a vanishing breed with the tactical sense and strategic acumen to know how to make Congress work. For voters rightly frustrated with paralysis on Capitol Hill, lawmakers like Mr. Van Hollen are the antidote.

The irony is that in the primary campaign, Ms. Edwards is wearing her intransigence as a badge of honor — and wielding Mr. Van Hollen’s pragmatism as a cudgel against him.

In her first broadcast TV ad, which began airing in Baltimore last week, Ms. Edwards lights into Mr. Van Hollen for having once suggested he’d consider Social Security cuts as part of a grand bargain, along with tax increases, that could finally right-size the nation’s long-term fiscal imbalance. Note that Mr. Van Hollen didn’t actually support Social Security cuts — he voted against them — but he merely said he’d keep an open mind about a blueprint for deficit cutting.

In fact, slowing the rate of growth of entitlement programs will have to be a part of any solution to the nation’s fiscal troubles. A progressive Democrat such as Mr. Van Hollen in the Senate could help ensure that any such changes affect the well-to-do and not the poor. That Ms. Edwards would attack Mr. Van Hollen’s reality-based thinking makes her a Democratic facsimile of Sen. Ted Cruz, the Texas Republican whose doctrinaire conservatism is a recipe for congressional gridlock.

Similarly, Ms. Edwards, whose own legislative record is thin, has also tried to mislead voters in suggesting that Mr. Van Hollen is somehow soft on the gun lobby. In fact, Mr. Van Hollen has been a leading champion of gun safety. In Annapolis, where he served in the state legislature before moving to Congress, he was a key sponsor of a 2000 law requiring mechanical safety locks on handguns sold in Maryland. In Congress, he was the driving force behind a bill to encourage states to require permits and background checks for handgun purchases.

Owing to partisan obstinacy and grandstanding, it’s become all but impossible to get things done in Washington and easier than ever to take shots at the few lawmakers, such as Mr. Van Hollen, who get their hands dirty seeking genuine ways to turn ideas into law.

No one doubts Ms. Edwards’s smarts, and her personal story of overcoming a humble background is inspiring. While she is a fine orator, Mr. Van Hollen is a legislator who can move the ball. That shouldn’t be held against him.