Thom Tillis, right, and his wife greet supporters at a election night rally in Charlotte, N.C., after winning the Republican nomination for the U.S. Senate on Tuesday. (Chuck Burton/AP)

North Carolina is this year’s ground zero in American politics. There are other highly competitive races around the country, but no contest so neatly captures all the conflicting currents of ideology, money, demographics and political tactics as the one between Sen. Kay Hagan (D) and her newly nominated Republican challenger, Thom Tillis.

Tillis, the speaker of the North Carolina House, more than survived his first battle as a Senate candidate. Facing a primary challenge Tuesday from both an opponent backed by tea party activists and another by some in the party’s evangelical wing, he cruised past the 40 percent mark he needed to avoid a runoff — with considerable help from the GOP establishment.

For the next six months, Tillis and Hagan will square off in a state that was the scene of fiercely contested presidential elections in 2008 and 2012 that produced a split decision, and where a conservative shift in its state politics will be every bit as central to the debate as will President Obama and his national record.

In a year in which each party considers turning out its base as critical to success, both sides have plenty of fodder to work with. Republicans will run against Hagan by linking her to an unpopular president, trashing the Affordable Care Act as big-government overreach and portraying her as a generally ineffective legislator. Democrats will attempt to connect Tillis to a series of new laws in North Carolina that provoked a strong backlash and generated “Moral Monday” protests in the state capital by Democratic interest groups. And they will tie Tillis to the billionaire Koch brothers, who have shown that they are prepared to spend down their fortune to help defeat the incumbent.

With Tillis as the Republican nominee, North Carolina’s Senate race offers perhaps the best laboratory in the country for a test of whether voters think the new Republican Party has shifted too far to the right or it stands for a smaller-government agenda that has a broader appeal than Democrats believe.

Sen. Kay Hagan, D-N.C., left, speaks with Bill Jeffries during an appearance in April in Durham, N.C. (Gerry Broome/AP)

The polls had barely closed Tuesday before Democrats sought to brand Tillis and, by implication, the North Carolina legislature as too conservative and out of the mainstream.

Justin Barasky, the Democratic Senatorial Campaign Committee’s press secretary, issued a statement that summed up the strategy: Tillis had “embraced extreme, far-right tea party positions,” it said. He would be “forced to defend his record as speaker, his fringe, far-right positions on issues . . . and an ever-growing load of ethical baggage.”

Precursor for 2016

Over the past two years, state government has taken a right turn in North Carolina under Republican Gov. Pat McCrory and his big majorities in the state House and Senate. Democrats consider it an agenda that harms the middle class and those most vulnerable. They cite as examples cuts in education spending, a decision not to enter into the expanded Medicaid program under the Affordable Care Act, the defunding of Planned Parenthood and cuts in extended unemployment benefits. They also say the state’s new voting rights bill would make it more difficult for minorities and others to vote.

Tillis and his allies will tell voters a different story, one that emphasizes the positive. They will draw a contrast between what they view as a burgeoning federal government under Obama (and Hagan) and a state government that has sought to rein in governmental excesses in favor of the private sector and individual freedom. Republicans see what Tillis helped lead as a reform conservative agenda that cut income taxes, eliminated the estate tax, did away with teacher tenure, provided more school vouchers and boosted charter schools.

All of this could become a trial run for the national debate in the 2016 presidential campaign — a choice between the record of the Obama administration and the record of Republican governors and legislatures in states where the GOP has unified control.

More than just the ideological competition between the parties makes North Carolina a telling example laboratory for the state of American politics. Long before Tuesday’s primary, outside groups already had found their way to the Tar Heel State, pouring millions of dollars into television ads.

Much of the money went to commercials from Americans for Prosperity, which is heavily funded by the Koch brothers and attacked Hagan for supporting the health-care law. Some of the rest went to ads by the GOP establishment, including from the Chamber of Commerce, boosting Tillis against his antiestablishment opponents: Greg Bannon, who had the support of Sen. Rand Paul (R-Ky.), and Mark Harris, a pastor who was supported by former Arkansas governor Mike Huckabee. Some was spent on attacks against Tillis by a pro-Democratic super PAC, the Senate Majority Fund.

With the candidates conserving their money, the outside groups accounted for 90 percent of the television advertising money spent during the opening phase of the campaign. Hagan and Tillis will begin to spend more heavily in the months ahead, but the role of the outside groups and “dark money” — spending from organizations that are not required to reveal their donors — will remain a central feature in North Carolina.

That is a reminder of how the balance of power has shifted away from political parties to quasi-independent groups — and how those groups now amplify the negative tone that often dominates political campaigns.

North Carolina is important for yet another reason. Its changing demographics are an example of the shifts that both parties are navigating in states nationwide. Obama’s campaigns drew more minority voters to the polls in North Carolina, helping him win a narrow victory there in 2008. He lost to Mitt Romney in North Carolina in 2012, but once again the state had a sizable outpouring of African American voters, whose registration rates are now at rough parity with whites.

North Carolina’s politics have been altered by a steady influx of new residents from other parts of the country. That has produced a distinct difference in political attitudes, with native North Carolinians and longer-term residents siding firmly with Republicans and those who have come to the state in the past decade or so more supportive of Obama in his two elections. Those changes have made North Carolina something of a purple state in presidential elections. Hagan is hoping to capitalize on those changes to save her Senate seat.

Finally, North Carolina will be a test for the new marriage of technology, data and analytics with old-fashioned political organizing. Obama’s campaign used its organizing prowess to good effect in 2008 and brought even more sophisticated techniques to its 2012 campaign, only to fall short in the end.

Costly, competitive, consequential

Democrats know that in a year in which they are clearly on the defensive, they will have to find a way to get every possible Hagan supporter to become a Hagan voter. Republicans say they are prepared to counter that with a more focused effort to turn out their own voters.

Both sides will claim to be seeking those elusive independents, but the bulk of the effort will be to energize and mobilize their bases, which almost guarantees that the campaigning will be extremely negative from now until November.

All that means that North Carolina’s Senate race will be costly, competitive and, in the end, consequential. The balance of power in the Senate could hinge on its outcome. Few races this year will offer a more compelling look at the politics of our time.