TRENTON -- Brigid Harrison was surprised when she saw the recent campaign ad on illegal immigration released by Republican New Jersey governor nominee Kim Guadagno.

"I found it rather uncharacteristic of Kim," Harrison, a political science professor at Montclair State University, said of Guadagno, the state's lieutenant governor, who is running to succeed Gov. Chris Christie. "It was not how she's played politics for the last eight years."

Indeed, the ad sounds less like Guadagno -- a plain-spoken, middle-of-the-road Republican -- than it does a far-right member of the GOP. You might even say it sounds like Donald Trump.

The ad jumps on Democratic opponent Phil Murphy's remarks that he would be willing to make New Jersey a "sanctuary state" to protect undocumented immigrants. And it suggests that Murphy's proposal would shield immigrants who are criminals.

"Make no mistake," the narrator says, "Murphy will have the backs of deranged murderers."

Down double digits in the polls and saddled with a massive fundraising disadvantage with about three weeks to Election Day, Guadagno hasn't made much headway with her main platform: a promise to cut property taxes.

Some say the ad could be a Hail Mary attempt to get a bump from Trump supporters and members of the Republican base who are deeply opposed to undocumented immigration.

"She definitely is taking a page out of the playbook of Trump and some prior races we've seen across the country where this (issue) has been used effectively," said Patrick Murray, director of the Monmouth University Polling Institute.

Whether that's effective in New Jersey -- a deep-blue and deeply diverse state where Trump is largely unpopular -- is the question.

Maybe, Murray speculates, another goal is to coax "some of the deep-pocketed conservatives across the country" to give Guadagno "some much-needed cash."

Others say Guadagno merely reacted when Murphy went too far to the left with his "sanctuary state" comment, and that any candidate in her position would take the opportunity to pounce.

Murphy, a former U.S. ambassador to Germany, made his remark last Tuesday during his first debate with Guadagno, surprising some political veterans.

Ricky Diaz, a spokesman for Guadagno's campaign, argued that the ad uses Murphy's "own words."

"I strongly object to the idea that this is a hard-right turn of any sort (for our campaign)," Diaz said. "Phil Murphy is way out of the mainstream. Even I'm old enough to remember when not protecting violent criminals in a sanctuary state wasn't right wing."

In broad terms, sanctuary cities refuse to cooperate with federal immigration officials who seek to find undocumented immigrants. A sanctuary state would be similar, only on a statewide basis. California became one last week. But sanctuary cities do not extend protections to violent criminals.

A Harvard-Harris poll from February found 80 percent of American voters say local authorities should have to report undocumented immigrants to federal agents. Some critics, however, have questioned the validity of that survey.

Carl Golden, a former press secretary for Republican Govs. Tom Kean and Christie Whitman, called the sanctuary issue "very, very divisive."

"There's an awful lot of people who think it's not a good idea," he said. "And I don't fault her for jumping on his comment."

Christie also defended Guadagno, saying the ad was "fair game" because of Murphy's remarks.

"He created this issue by grandstanding with his cliches," Christie said at a news conference Friday. "Now he has to pay for it by answering these questions."

Democrats have denounced the ad as racist. Former Vice President Joe Biden called it "the return of Willie Horton." Daniel Bryan, a spokesman for Murphy's campaign, said it's "vile, despicable, and false." And Murphy himself said at a rally Sunday that Guadagno is "trying to scare people to vote."

The ad suggests that Murphy would have protected Jose Carranza, an undocumented immigrant from Peru who was convicted for killing three Newark teenagers in 2014. Carranza was previously arrested for raping a child and released on bail.

The commercial does not include how Murphy has called those murders "heinous" and said that Carranza should have been prosecuted.

Guadagno defended herself in a speech Sunday to the Association of New Jersey Rifle and Pistol Clubs.

"Somehow today, the fact that I have said I want to protect the people of New Jersey against anyone who would commit a violent crime against anyone in New Jersey -- I somehow have become a racist?" she asked.

Through five days, the ad was viewed on You Tube a modest 9,300 times as of Monday morning -- much more than the other videos on Guadagno's page, though far from "viral" territory.

But it has gotten Guadagno attention with Trump's key demographic: She landed an in-studio interview on Fox News' "Fox & Friends" the morning it debuted.

A media buyer who requested anonymity to speak candidly said Guadagno's ad is airing mostly on Fox News in New York City and Philadelphia. Guadagno's campaign declined to discuss details of the ad buy.

Still, Ben Dworkin, director of the Rebovich Institute for New Jersey Politics at Rider University, said it's unlikely the issue will hurt Murphy.

"If it were a state like Michigan or Wisconsin or Pennsylvania or a heavy Trump state, it would be a bigger thing," Dworkin said.

Harrison, of Montclair State, added that Guadagno's "Trumpian" depiction of undocumented immigrants could cause her to hemorrhage support among Hispanic voters -- a bloc that the Republican Party in the state has taken steps to court in recent years.

There is one thought that the Nov. 7 election will draw a low turnout, with Murphy not exciting the Democratic base, and that might allow Guadagno to rally Republicans with her property-tax and immigration appeals.

"I think it resonates with these folks," Dworkin said of the ad. "But we should remember: Trump didn't win New Jersey last year."

Brent Johnson may be reached at bjohnson@njadvancemedia.com. Follow him on Twitter @johnsb01. Find NJ.com Politics on Facebook.