Communication involves more than words, and nowhere is that more apparent than in a political campaign.

Bill Clinton strategist James Carville hung a sign in the then-candidate’s campaign offices reminding Clinton to stress three points: 1) Change vs. more of the same. 2) The economy, stupid. 3) Don’t forget health care.

Clinton won, and many analysts credited his victory to No. 2 on that list. It’s been used so much it’s become a cliché. Mitt Romney has been emphasizing these same three issues and finds himself consistently even or behind in the polls — and apparently slipping in some key swing states.

Maybe Carville wasn’t as smart as it appeared at the time. Maybe analysts should be listening less to Carville and more to the late communication theorist Marshall McLuhan, who coined another famous phrase: “The medium is the message.”

Tone of voice, expression and body language communicate the majority of our thoughts and feelings, and this kind of communication doesn’t work well to convey specifics. Their role is to paint a broad-brush picture of trustworthiness, likability, insightfulness and, perhaps most importantly, compassion. Does this person care?

There’s a good reason Republicans (and a lot of other folks) hold Ronald Reagan in such high esteem. Sure, he talked tough. But he also came off as good-natured, compassionate and optimistic. Policy issues didn’t stick to him, and it wasn’t because he wore Teflon; it was because he seemed like a trustworthy and upbeat individual.

All great political communicators have one thing in common, and it’s not their mastery of issues such as the economy or national defense or same-sex marriage or abortion. They are able to communicate that they care.

Mitt Romney appears to be figuring this out and has begun to tell people, “I care.” But saying it isn’t enough. You have to convince your audience, and that’s where nonverbal communication comes in. Do you communicate the kind of self-assurance that radiates optimism and inspires others? If so, you’re likely to win.

Walter Mondale lost in 1984 because Reagan connected with the electorate’s need for optimism. He told us it was “morning in America.” Mondale told voters he would raise their taxes.

George H.W. Bush didn’t lose in 1992 because of the economic downturn; he lost because he appeared not to care about the downturn and how it was affecting voters. His son, by contrast, appeared to care about voters quite a bit — especially in the aftermath of Sept. 11. He ran on a platform of “compassionate conservatism,” and he won two elections over men who appeared less likable than he was.

In fact, in every presidential election I’ve voted in, the more likable candidate has won: the candidate who appears more compassionate and connected with voters. Reagan, George H.W. Bush (in his first election), Clinton, George W. Bush and Barack Obama each seemed more compassionate than the other guy. Congenial and optimistic beats stiff and wonkish every time.

Romney should be worried that Obama has been coming out ahead in polls about likability, because likability wins elections — likability, sincerity and compassion. Those are the three messages I’d hang in my candidate’s headquarters if I were running a campaign.

Romney has been banking on the bad economy to deliver him a victory. But if politics were about the economy alone, Franklin Roosevelt wouldn’t have won reelection in history’s biggest electoral vote landslide in 1936 … even though he had failed to end the Great Depression. No, it’s not the economy, stupid. It’s fireside chats and cowboy hats. It’s grieving with victims’ families after Sept. 11.

The medium is the message. The candidate best able to master it will win.

Steve Provost is a Tribune copy editor.