The first debate is around the corner. Early voting begins in a month. And Election Day is just seven weeks away.

And yet, polls show Rep. Joe Heck is still ahead in the Nevada Senate race.

Can it last?

In an election year full of surprises, Heck’s sustained edge over Democratic nominee Catherine Cortez Masto is yet another unexpected but important twist. The doctor and brigadier general in the Army Reserve is the GOP’s only plausible chance to pick up a Senate seat, a victory that could very well guarantee the party hold its Senate majority as it defends nearly a dozen seats elsewhere.

Republicans are also giddy at the prospect of winning a seat held by the retiring Sen. Harry Reid, a chance the GOP blew when it nominated the gaffe-prone Sharron Angle during Reid’s 2010 re-election bid.

Heck’s small advantage comes despite Nevada’s growing Democratic lean in federal races, driven by its diversifying electorate. For much of the election cycle, Democrats had been confident their demographic edge offered a sure path to victory in the Senate race.

They still think it will — but they concede they have a lot of work left to make sure of it.  

“It’s extremely close at all levels of the ticket,” said Yvanna Cancela, political director at the influential Culinary Union. (The Culinary Union has endorsed Cortez Masto.)

The most difficult test

Even Heck’s allies, however, acknowledge the most difficult test will come in the election’s final weeks, when he’ll face a barrage of attacks questioning his record on immigration, entitlement programs and — above all — his continued support of GOP presidential nominee Donald Trump.

Democrats surmise that the state’s left lean and Trump’s presence on the ticket will eventually prove too much to overcome for Heck, whose early edge they attribute mostly to name recognition.

“The level of anger toward Trump and his policy proposals and rhetoric is real,” Cancela said. “And I think the more Joe Heck is revealed to be aligned with Donald Trump, the better it is for Catherine.”

Heck’s lead is, in part at least, due to Trump. The GOP nominee was expected to struggle in Nevada, a state President Barack Obama won by nearly 5 points four years ago, because of its soaring Latino and Asian-American population.

Instead, Trump has kept his race close there because of his strong support among white working-class voters. The last three reputable surveys have shown Democrat Hillary Clinton with leads of 1 point, 2 points, and a Trump lead of 1 point.

Democrats are confident that Trump will fade, enough that the party’s home-stretch strategy will still heavily rely on linking Heck and Trump together in paid media.

That’s actually an uncommon approach: Many Senate Democratic candidates, in contrast with what they say in interviews, press releases, and speeches, don’t use Trump in TV and radio ads.

But two weeks ago, Cortez Masto’s campaign began running a TV ad that contrasted Heck’s support of Trump with Nevada GOP Gov. Brian Sandoval and Sen. Dean Heller, who have both said they would not back the GOP nominee. Aides to Cortez Masto’s campaign say that ad is still running in Nevada.

On Tuesday, the Service Employees International Union and iAmerica Action announced they would begin a new Spanish-language radio ad, backed by a $1 million buy, linking Trump and Heck on immigration.

Room to grow

Cortez Masto might have room to grow with Hispanic voters. A Univision poll this month found her edge among Latinos was just 34 points, 12 points smaller than Clinton’s lead. Thirty-eight percent of Hispanic voters didn’t know enough about her to form an opinion (41 percent said the same of Heck).

But Heck is a thrice-elected congressman from a battleground House district in southern Nevada, who won his elections in part because of his broad appeal to Asian-American and Hispanic voters.

Nevada Republicans are confident that voters see a distinction between Trump and Heck, no matter how hard Democrats try to blur the line between the two men. And they fire back that Cortez Masto and the Democrats have their own problems at the top of the ticket, with Clinton’s favorable numbers hardly better than Trump’s in some polls.  

“It remains to be seen if Hillary Clinton is going to drive voters to the polls the way Barack Obama did,” said Brian Baluta, a Heck campaign spokesman.

Baluta says he’s confident that in a close race, the coordinated ground game between the Republican National Committee, the Trump campaign, and the Heck campaign will offer a crucial advantage. The effort surpassed a million voter contacts in mid-August, he said, a month earlier than Nevada Republicans did in 2012.  

“It’s going to be fought tooth-and-nail,” the spokesman said, “because this is the race that is going to decide the Senate.”