Manchester, New Hampshire (CNN) Sen. Kelly Ayotte has often found herself in a familiar spot with Donald Trump: Keeping her distance.

But in this fiercely independent state, Ayotte is gambling that voters might reward her for rebuking her own party's nominee. She has criticized Trump and will not endorse him -- yet still plans to vote for the billionaire in November.

"I will take on my own party," Ayotte told CNN in Nashua Monday. "I really believe that this is a big issue in this race -- that I am the one candidate that will stand up to whomever is in the White House to do good things when we can work together -- also when it's wrong to stand up to them."

Ayotte is one of more than a half dozen Republican senators whose fate this fall is critical to saving the GOP's beleaguered Senate majority. And with Trump's standing now eroding rapidly in battleground states, Republican senators need to convince Hillary Clinton voters to split their ticket, warning of the perils of one-party rule in Washington.

For Ayotte, that means spotlighting her criticism of Trump while painting her Democratic opponent, New Hampshire Gov. Maggie Hassan, as a candidate who would simply toe the party line. Selling voters on her independent bona fides may be her best hope.

"The people of New Hampshire need to know are you ever going to disagree with your nominee? And unfortunately, Gov. Hassan has not," Ayotte said.

Democrat Maggie Hassan asked 3x if @HillaryClinton is honest and trustworthy. She never says yes. #NHSEN @mkraju https://t.co/g0uhM7VN2o — Zach Wolf (@zbyronwolf) August 16, 2016

In an interview in Boscawen, New Hampshire, Hassan said she does differ with Clinton on some issues -- like the former secretary of state's support for closing the prison in Guantanamo Bay and on an online sales tax issue. But Hassan is aligning herself closely with Clinton, stumping with Sen. Tim Kaine at a Manchester rally last weekend and touting the former secretary of state's candidacy in an interview.

"I think that Hillary Clinton and I work for many of the same things, expanding middle class opportunity so that everybody who wants to work hard to get ahead can stay ahead," Hassan said Monday

Yet, being tied too closely with Clinton carries its own risks, with 64% of voters nationally in a recent CNN-ORC poll saying that the former first lady is not honest or trustworthy.

Asked three times if she believes Clinton is honest, Hassan would not answer directly. "I support Hillary Clinton for the presidency because her experience and her record demonstrate that she is qualified to hold the job," Hassan said.

Asked again if she believed Clinton is honest, Hassan touted Clinton's agenda. And asked a third time, Hassan ultimately said: "She has demonstrated a commitment always to something beyond her self, bigger than herself."

The Hassan campaign later clarified the governor's statement, saying she does indeed believe that Clinton is honest.

In the interview, the governor also did not express concerns over FBI Director James Comey's sharp criticism of Clinton's handling of classified emails as "extremely careless."

"If she could rewind and do it differently she would," Hassan said. "But she can't do that. What she has had to do is learn from that mistake and move forward.... And so that's what I expect her to do."

Difference between vote and endorsement?

Despite Trump's slumping numbers in her state, the GOP nominee still has a vocal base of support, given that he routed his fellow Republicans in the presidential primary here in February.

And that has made it harder -- if not impossible -- for Ayotte to completely separate herself from Trump, even as she has criticized his proposed ban on Muslims entering the United States and his fight with a Gold Star family.

Ayotte says there's a difference between voting for someone and endorsing them.

"There's actually a big distinction: Everyone gets a vote, I do too," Ayotte said. "And an endorsement is when you are campaigning with someone."

Ayotte said the situation differs from 2012 when she was barnstorming the state with Mitt Romney -- something she won't do for Trump when he comes to the Granite State.

"While he has my vote he doesn't have my endorsement," Ayotte said of Trump. "I'm going to continue to focus on my race and getting out to people what I have done and getting results for people in New Hampshire."

Hassan, sensing an opening, fired back.

"I think people should hear that statement for what it is: She is trying have it both ways," Hassan said. "What you see the senator doing is saying she will put her party before the national security and safety of our country. I think that is inexcusable."

And giving Democrats fodder, Ayotte refused to say twice if she trusted Trump having his finger on the nuclear codes, launching into a criticism of President Barack Obama and saying Congress would be able to stand up to a President Trump.

"I think, again, we have a system, a strong system, of checks and balances," Ayotte said. "Certainly when he is elected, if he is elected, I would hope that he will surround himself with very knowledgeable people."

What has put Ayotte in an awkward spot was the decision by her fellow New England senator, Maine's Susan Collins, to announce last week that she would not vote for Trump, warning he would make a perilous world "even more dangerous."

Asked about that contention, Ayotte said: "I respect her but each person has to make their own individual decision on who they're going to vote for. And so that's what I've done."

Ayotte suggests Trump release his tax returns

Ayotte's relationship with Trump was thrust back in the news when the nominee told The Washington Post earlier this month that the senator was "weak." A few days later under pressure from his party, Trump announced he would support and endorse Ayotte's candidacy.

Sensing an opportunity to again distance herself from the top of the ticket, Ayotte pushed back.

"Hey listen, I call it like I see it," Ayotte said. "And when he criticizes me, I just said very clearly if I have his endorsement or not, I'm going to continue calling it like I see it for the people of New Hampshire."

Asked if she would stand up to Trump and demand the release of his tax returns, Ayotte suggested he should. But she didn't seem too concerned about it.

"I think that in the presidential race it's better if he releases them," Ayotte said. "But he's got to make that call."