Longtime Republican At-Large Councilmember Carol Schwartz moments ago gave a concession speech after a tightly contested primary battle with upstart Patrick Mara. With less than 20 percent of the precincts in, Mara held a commanding 62-38 percent advantage. According to Loose Lips columnist Mike DeBonis, that early tally doesn’t include most Ward 3 precincts, where quite a few Republican voters reside—which raises some questions as to why Schwartz bagged out so early.

The 68-32 margin looks a lot more impressive as a percentage than do the raw numbers behind it. Mara has garnered 424 to Schwartz’s 258. That’s what happens when about three-quarters of your city’s voters are Democratic.

The real story here is the insularity of the Republican primary. Schwartz is one of the city’s most popular politicians, as evidence by her historically strong showings in general elections, where she has pulled down enormous chunks of the voting population. But this is a closed Republican primary, and her opponent essentially out-Republicanned her.

Buoyed by big dollars from pro-biz groups, Mara hammered Schwartz with campaign literature that described her as, well, a Democrat in Republican clothing. Much of Mara’s support came from a D.C. business community peeved over Schwartz’s championing a sick-leave bill that imposed new costs on D.C. firms.

In a brief interview with Loose Lips this evening, Schwartz said that she’d “never wage a write-in campaign” to leverage her popularity with the city’s Democratic supermajority. Nor will she ever endorse Mara, on account of the “guttural nature of the campaign.”