CONWAY, N.H. (AP) — In one of the country's most important Senate races, Republican U.S. Sen. Kelly Ayotte and her challenger, Democratic Gov. Maggie Hassan, clashed Friday over topics including taxes, immigration and the Iran nuclear deal in their first debate.

Polls continue to show the race in a dead heat, and roughly $100 million in outside spending is expected to pour into the state by Election Day. Democrat Hillary Clinton is leading in the state over GOP presidential nominee Donald Trump. But Ayotte, who said she would vote for Trump but wouldn't endorse him, has kept the race close by playing up her moderate positions.

Despite the national implications, neither Clinton nor Trump was a big part of the conversation Friday — though Hassan did call Trump "temperamentally unfit" at one point.

The debate in Conway was largely congenial, though both candidates took swipes at each other's record.

Hassan, a two-term governor who also has been state Senate majority leader, played up the fact that the state passed two balanced budgets under her watch without a sales or income tax and approved tax cuts for small business over several years. If she wins, Hassan said, she would focus on fiscal responsibility and work to close tax breaks for big oil companies and Wall Street.

"As we work to balance the budget, I won't do it on the backs of people who are in retirement with Medicare and Social Security," Hassan said. "(Ayotte's) approach to balancing the budget has been on the backs of seniors."

Ayotte countered that she "looked for ways to save money" on every committee she served on. Playing up her bipartisan credentials, she said she'd worked with colleagues to eliminate wasteful programs, including an agency that "just produces reports that you can get online." She also denied accusations that senior citizens would be hurt by her positions on Medicare and Social Security.

"My mother is on Social Security so of course I don't want to harm my mother," Ayotte said. "But one thing I want to do is make sure these programs are there and that means working together to come up with a sustainable path."

Some of their biggest disagreements dealt with international affairs, especially the Iran nuclear deal supported by President Barack Obama. Ayotte voted against it.

Hassan said the "imperfect" Iran deal was the "best way to keep Iran from having a nuclear weapon — something that must never happen."

Ayotte countered that the deal allows Iran to keep its infrastructure and noted that the country has conducted ballistic missile tests since the agreement was signed.

"The only reason you need a ballistic missile is to deliver a nuclear weapon either to your allies or the United States," she said.

While they agreed on the need to defeat the Islamic State group and take on global terrorism, the candidates emphasized different aspects of that fight. Ayotte talked about thoroughly vetting anyone trying to enter the U.S.

Hassan mentioned the need to increase air strikes, strengthen moderate military forces on the ground and bar any terror suspects from owning guns — something Hassan accused Ayotte of not supporting.

Ayotte said she supported bipartisan efforts to keep guns away from people who were deemed too dangerous to get on a commercial flight while ensuring law-biding citizens' constitutional rights are protected.

The candidates did agree on a few issues, like fighting climate change and working to improve the Affordable Care Act.

And the debate had some lighter moments, including when each talked about her favorite teacher and favorite hiking spot in the state.