The threshold question facing all Democratic candidates is what is the rationale for how they spend their money? The overwhelming allocation of the $6 million Mr. Ossoff’s campaign has spent has gone to paid ads — nearly $3 million on media buys and $2 million on online ads.

Who is the intended target of these ads? Are those expenditures targeting the 125,000 Democrats to inspire them to turn out again, or are they designed to convince Republican frequent voters that Mr. Ossoff isn’t such a bad guy?

In addition to the Democrats who voted in November, there are tens of thousands of African-American, Latino and Asian-American eligible voters in the district, but their participation is usually lower for many reasons. That is a solvable problem for a candidate with many millions of dollars and a résumé that includes an internship with John Lewis, the civil rights legend who represents a nearby district.

The cost of turning out an infrequent voter is roughly $30 to $50 per voter. Devoting just $1 million of Mr. Ossoff’s enormous financial haul to such a program would increase minority voter participation by about 25,000 voters, bringing him much closer to the 75,000 vote number he needs.

There are also some signs that the Democratic Party is “getting it.” The Democratic Congressional Campaign Committee has signaled a shift from previous practice by assigning nine staff members to the Georgia special election to help with turnout instead of simply running television commercials, as it has frequently done in past elections.

If Democrats want to do well in 2018, they need to start spending money now on programs to increase voter turnout then. Over the past decade, the party whose voters have been least inspired to participate in the midterms has lost control of the House of Representatives.

In 2006, Republicans held the majority in the House, but their voter turnout plummeted, with nearly twice as many Republicans staying home as Democrats, allowing enough seats to change parties to make Nancy Pelosi the speaker.