Supporters who want to bring MARTA into Gwinnett County remain optimistic, but the Tuesday vote will be close. There's every chance that come 10 p.m., election officials will announce that the initiative has been defeated.

If that is the case, the vanquished shouldn’t despair, and the victors will have no cause to gloat.

Gwinnett voters are being asked to decide – yes or no — whether to approve a one-cent sales tax that would allow MARTA to extend heavy rail from Doraville into Norcross, and operate a 50-mile bus rapid transit system.

But “yes or no” isn’t the real choice. The real choice is “now or later.”

Demographically and thus politically, transit in Gwinnett is something close to inevitable. If the measure is lost on Tuesday, surging Democrats say they’ll push for another vote in 2020 – or two years after that if necessary.

There’s an argument to be made that Republicans, even those who sought to sabotage the vote by moving it from last November’s general election to this orphan date in March, would be smart to help them. Sooner rather than later.

A quick sketch of the situation: On Monday, John Garst of Rosetta Stone Communications, the only firm with public polling on the referendum, noted that white voters had made up two-thirds of the 20,000 or so early votes cast so far, and 90 percent were over the age of 40. Garst’s polling had indicated that two-thirds of white voters opposed the MARTA referendum, as did a majority of those over the age of 40.

I passed Garst’s stats to Go Gwinnett, the group advocating for the referendum. Spokesman Brian Robinson said he couldn’t vouch for the polling, but conceded the larger point.

“It’s true that the demographics that have turned out strongest in early voting are those more likely to vote no. But Gwinnett saw similar demographic patterns in the primary and general elections last year – and the electorate turned out to be one that would heavily favor expanding transit options,” Robinson said.

Translated: Stacey Abrams, the Democratic candidate for governor, carried Gwinnett by more than 56 percent of the vote.

Concluded Robinson: “If you surveyed the whole county, support for the referendum would enjoy a big majority, but the majority has to show up.”

This dilemma was intended. My fellow Journal-Constitution columnist Bill Torpy this week quoted John Heard, a Gwinnett County commissioner who urged shifting the MARTA vote from Nov. 6 to March 19, as saying that House Republican leaders had encouraged the move, fearing that a transit vote would boost the GOP casualty list in the general election.

Heard was among the defeated. Two Democrats, Ben Ku and Marlene Fosque, now sit on the five-member Gwinnett County Commission.

So let’s do a little war-gaming that assumes a defeat of the Gwinnett MARTA vote on Tuesday. There are two likely paths for what happens next.

Scenario No. 1: Charlotte Nash, the Gwinnett County Commission chairman, has been indefatigable in her support for the MARTA referendum. A Republican, she’s up for re-election in 2020, but hasn’t yet said whether she’ll seek another term.

If the MARTA vote fails, it would be all but impossible for Nash to seek office again in 2020. But there is liberation in knowing you’ll never have to ask for another campaign contribution.

Nash could work with the two Democrats on the commission to schedule a new MARTA vote for November 2020, concurrent with a U.S. Senate race and President Donald Trump’s re-election bid.

According to the terms of the deal at stake on Tuesday, Gwinnett would hand over 29 percent of the proceeds from the new one-percent sales tax to MARTA for operational purposes. The rest would be pushed toward the building of infrastructure.

The deal has raised the eyebrows of many officials in DeKalb and Fulton. In those originating counties, plus Clayton, 50 percent of the penny sales tax goes toward operations.

Whether that deal can be put on hold for an extra 20 months would be an open question, but changes might be kept to a minimum.

Scenario No. 2: The MARTA vote goes down in defeat on Tuesday, and the Gwinnett County Commission decides to walk away from the issue. The defeat, and its engineering by a GOP fearful of Gwinnett’s changing demographics, become Democratic talking points leading up to the 2020 election.

“The traffic will still be there,” said Curt Thompson. He’s a former state senator and an announced Democratic candidate for the chairmanship of the Gwinnett County Commission. Thompson said he remains optimistic that the MARTA vote will succeed, but knows what will happen if it doesn’t.

In 1990, Gwinnett voters rejected a referendum on MARTA by a 2-to-1 margin. “That shook the county to its roots,” Thompson said. Twenty-eight years would pass before county officials would touch the issue again. If Tuesday’s vote fails, a transit connection to Atlanta can’t be shelved for another three decades. “We can’t create a Gwinnett bus system that doesn’t go anywhere, just to say we’ve done something – when we haven’t,” Thompson said.

Let us suppose that Thompson or some other Democrat wins a seat on the Gwinnett County Commission in 2020 – which does not require a large stretch of the imagination. One of the new commission’s first actions would be to schedule another MARTA vote, most likely for November 2022.

That would put Gwinnett on the same transit voting schedule that economic development rival Cobb County is contemplating. “And we were trying to get ahead of Cobb,” Thompson said.

A Democratically controlled Gwinnett County Commission is likely to be less suspicious about bonding with MARTA. The bargain between Gwinnett and MARTA could tip more toward a 50-50 split of the penny sales tax, as in DeKalb, Fulton and Clayton counties.

But here’s the thing: Last August, Republicans were so fearful of a Gwinnett transit vote in November 2018, that they pushed it into 2019. Under this scenario, should the MARTA referendum fail on Tuesday, Republicans would be faced with a repeat of the situation in 2022. But this time, they’d have no mechanism to avoid it.

President Donald Trump might or might not be in the White House. But almost certainly, Gov. Brian Kemp would be seeking another term. Maybe he’d be running against Stacey Abrams again, maybe not.

Gwinnett went Democratic in 2018, when Kemp won the governorship with 50.2 percent of the vote, and is likely to do the same in 2022. But whether that Democratic margin in Gwinnett grows could matter a great deal in statewide votes for governor and every other state constitutional office.

So if Gwinnett’s MARTA vote fails on Tuesday, the immediate question for Republicans is a simple one: Do you let the issue of transit in that county linger for two years, or four?