Campaigns for president, U.S. Senate and House, governor, and hundreds of other political races have spent staggering sums to market their candidates to North Carolina voters. But will all that spending really change anyone’s mind?

If you look at empirical research, you’ll find mixed evidence, at best, for the efficacy of political expenditures. Self-styled “reformers” like to claim otherwise, but it is exceedingly difficult to “buy” an election if it is not already extremely close. And even then, lots of campaign dollars are wasted.

Based on what I’m hearing and seeing during the final days of the 2020 election cycle, it strikes me that the result of North Carolina’s highly competitive races hinge on the priority lists that voters have scrolling in their heads.

If limiting the spread of COVID-19 is your chief concern, you’re probably voting Democratic. In a recent ABC News/Washington Post poll of North Carolinians, for example, likely voters who were most worried about themselves or their immediate family members catching the virus were breaking 68% for Joe Biden. Among voters less worried about catching it, the preference was 80% for Donald Trump.

If the related issue of health care is motivating you to cast your ballot, you are also probably casting it for Democrats. Asked by Monmouth University’s polling unit which of the two presidential candidates they would trust most to make health care accessible and affordable, 46% of likely North Carolina voters picked Biden and 38% picked Trump.

On the other hand, if spurring economic recovery is your top priority, you are probably voting Republican. In a Reuters/Ipsos survey, 51% of likely North Carolina voters said they thought Trump would be “better at managing the economy” while 43% said Biden would be better.

Other key issues motivating Republican-leaning North Carolinians are crime and social unrest. In the September Civitas Poll, 58% of those who thought law and order was a “major problem” said they were voting for Trump. Among those who said it was only a “minor problem” or “no problem” at all, Biden was the choice of about eight in 10 respondents.

There are a few other issues that voters mention in the North Carolina polling I’ve seen — education, the environment, the fate of the Supreme Court — but the top choices tend to be COVID, the economy, law and order, and health care. If you look at the emails, flyers, and ads targeting voters in the last days of the campaign, the vast majority of the messaging involves these four issues.

While there may be a few North Carolinians left whose views about a candidate can still be changed by a persuasive message, they aren’t all that likely to vote in any event. Most of the remaining swing voters already have their minds made up about which candidate would do the best job on a given issue. What campaigns are really trying to do, more often than not, is to increase the salience of their stronger issues and diminish the salience of their weaker ones.

In other words, Democrats want these voters heading into the polls thinking about fighting COVID-19 and reforming health care. The GOP would rather see them cast their ballots while thinking about boosting the economy and enhancing public safety.

That’s why images are so important in political messaging. Whether we like it or not, human beings are strongly influenced by visual (and aural) cues. The mailer waiting in your mailbox this afternoon may not contain much in the way of a substantive policy argument. Indeed, it may contain only a few words. Its pictures and graphics are the real message. Similarly, political ads are designed to be effective even when the sound is off, which is often the case as viewers fast-forward their recorded shows or watch videos on their phones.

These campaign tools are designed to prime you to think about an issue, not persuade you what should be done about it. That’s what makes them a comparatively good use of money.

John Hood (@JohnHoodNC) is chairman of the John Locke Foundation and appears on “NC SPIN,” broadcast statewide Fridays at 7:30 p.m. and Sundays at 12:30 p.m. on UNC-TV.