Nancy Floreen in Gaithersburg on Aug. 6. (Sarah L. Voisin/The Washington Post)

THE TWO plausible candidates for Montgomery County executive agree on one big thing — that the county must stimulate economic growth and encourage new business if it is to maintain its excellent schools and enviable services. They’re right. Given that common goal, the choice in the election Nov. 6 is stark: Nancy Floreen, a veteran Democratic county council member running as an independent, has a lengthy track record showing she can be successful. By contrast, Democratic nominee Marc Elrich, her fellow council member, has an equally lengthy record — and, in many cases, an extreme one — that is disqualifying.

Ms. Floreen — iron-willed, no-nonsense and deeply experienced — would make an exceptionally competent leader. Mr. Elrich, Montgomery’s foremost opponent of business and growth for more than a decade, is also well-versed on the issues, but he would imperil the county’s economic and fiscal prospects. (A third candidate, Republican nominee Robin Ficker, is a rabble-rouser notorious for heckling at Washington Wizards games, as well as for repeated disciplinary actions taken against him by Maryland’s Court of Appeals.)

As the Democratic standard-bearer in a heavily Democratic county, Mr. Elrich has collected (often tepid) endorsements from most local elected leaders. Yet in private conversations, many of those same leaders say they will vote for Ms. Floreen, and express deep misgivings about the harm Mr. Elrich could do if elected.

Montgomery is Maryland’s most populous and prosperous locality, but it has missed out on boom times and now faces serious problems: a virtual standstill in job and business growth this decade, a gap between haves and have-nots and an anemic revenue outlook. In that climate, Ms. Floreen, a council member since 2002 and a planning commission member before that, is the right choice.

She has demonstrated spine in insisting on fiscal discipline and grappling with spiraling labor costs, which account for 80 percent of the county’s budget outlays. As council president in 2010, during the fallout from the Great Recession, and again in 2016, she was a model of budgetary sanity and restraint. No one in local politics has been a more effective advocate for affordable housing. And while Ms. Floreen accepts campaign contributions from developers, which Mr. Elrich does not, she is no one’s puppet, and has shown a capacity to balance and stand up to business as well as labor.

By contrast, Mr. Elrich, a council member since 2006, has been the bane of the business community, wasting few chances to vilify and obstruct projects large and small, including the Fillmore, a popular live-music venue in Silver Spring. No one doubts his acuity or command of detail — he devised an ambitious blueprint for a bus rapid transit network — but he is also prone to bombast, warning a new light-rail line would cause “ethnic cleansing.” A longtime champion of rent control, he would oppose most new residential construction, thereby crimping the future supply of affordable housing, and impose greater costs on economic development, further jeopardizing the county’s prospects for revenue growth to support schools, parks, libraries, public safety and social services.

Mr. Elrich, heavily backed by county employee unions, risks being beholden to them: Witness his imprudent pledge to invite labor leaders to sit in on hiring interviews for county department heads. He acknowledges Montgomery is strapped for money but would be unlikely to hold the line in looming contract negotiations with county unions.

County employees work hard, provide excellent services and should be compensated accordingly. But their interests and those of taxpayers both must be taken into account.

Having voted in 2010 to boost Montgomery’s reserve fund, Mr. Elrich now waffles on whether he would protect it, heightening fears that an Elrich administration would endanger Montgomery’s credit rating and raise its borrowing costs.

A tough-minded pragmatist, Nancy Floreen is the clear choice for county voters determined to protect and improve the county’s schools, parks and future.