Will the latest attack ads against Trump work?

For months, every GOP presidential candidate has thrown jabs at Donald Trump, but none of them seemed to stick.

Now, the super PAC backing John Kasich, New Day for America, has announced it will spend $2.5 million in New Hampshire attacking Donald Trump. It released the first attack ad on Monday.

Jeb Bush tried this approach back in September and without any effect, but the latest Kasich-backed PAC ads may bring different results since they hit Trump where he is most vulnerable – in foreign affairs.

Donald Trump
Gretchen Ertl | Reuters
Donald Trump

The Bush attack ads were never precise. They tried to position Trump as too liberal for the GOP base. The ads pulled sound bites from previous Trump interviews where he acknowledged he was "very pro-choice," and supported universal health care as an entitlement. They even replayed interviews where Trump said he identified as a Democrat on some issues. While this attack ad was targeted for the right wing of the party, it also gave Trump a boost with the more moderate base of the party. There is a portion of the electorate that is pro-choice and have benefited from universal health care.

But the New Day for America attack ads are actually hitting Trump where he is most vulnerable. These attack ads are precise – and not blanket jabs.

The Kasich-backed PAC ad begins with a voiceover, saying "On-the-job training for president does not work ... Our lives depend on a Commander-in-Chief with experience … who understands the world." The voice then plants seeds of doubt by reinforcing Americans fear of terrorism.

The Kasich-backed PAC ads hit Trump exactly where Americans are most fearful of him as a leader. Does he have what it takes to keep us safe from terrorists? The thought is now planted.

This is also the place where Kasich is strongest. With 18 years in Congress and two terms as governor of Ohio, no one is attacking Kasich as being inexperienced. He knows this and so does his super PAC.

In a state like New Hampshire, this ad buy will go far. The media buy will be more expensive in local markets that intersect with Boston, but it will be nowhere near the cost of a national or New York-centered media blitz. The message will also spread far in the local cable-news outlets that hit the New Hampshire voters.

So, do these attack ads have a shot at knocking Trump off his perch?

The key to fending off a political attack is to pre-empt it. And Trump has already shown he is an adept, agile fighter who gets in front of the punches. If he were to jump in front of these attack ads with his bullhorn and start hitting foreign affairs hard, he could defend his turf.

And knowing Trump, he will. It's not in his DNA to back down from any fight – whether it comes from the left or the right. He might be a novice in the political ring, but he's a New York City street fighter and those are the ones who usually throw the first punch.

Commentary by Mark Macias, head of Macias PR, a global public relations firm that has run media and branding campaigns for politicians,tech start-ups, financial firms, nonprofits and companies. He's also author of the book, "Beat the Press: Your Guide to Managing the Media." Follow him on Twitter @markmacias.