After many months of delay, Pope Benedict’s third encyclical arrives tomorrow. And at least one observer is asking: “Will anybody care?”

In the days leading up to this week’s scheduled release of Pope Benedict XVI’s latest encyclical, there’s been a quickening of speculation about what it will say. We know the name: Caritas in Veritate (“Charity in Truth”). And we know generally that it will be about social topics, including the effect of the global economy, environmental issues and business ethics.

From the left comes predictions that steadfast capitalists will not be happy. From the right comes scoffing that liberals don’t understand this pope.

But I have a different question: How much does it matter what the encyclical says? Who will pay attention? Is there any evidence that a papal pronouncement in 2009 has the power to change minds or even behaviors? Because if not, this will ultimately be of interest only to future religious historians.

Catholics themselves are raising the issue. As the Catholic News Service reported last week:

When Pope Benedict XVI’s social encyclical is released, Catholics shouldn’t just ask, “What does the pope say I’m doing right?” but “What should I do to act more morally?” said the Carl A. Anderson, head of the Knights of Columbus.

Will that happen?

Benedict clearly hopes his words will have an impact. The release of the encyclical — delayed since last year – arrives days before the scheduled opening of the G8 summit in Italy, not to mention President Obama’s scheduled meeting with the pope at the Vatican .

But does anybody really expect the world’s leaders to spend the night before the summit combing through the papal recommendations? (Of course, that’s probably too short a time horizon to evaluate a statement from an institution that understands itself as operating through millennia. )

Assessing the potential impact of the encyclical is a question of politics and even sociology. So I sought out some folks savvy in those areas.

The Rev. Thomas Reese, former editor of America magazine, is a senior fellow at the Woodstock Institute at Georgetown University. He’s one of the experts who has speculated about the content of the encyclical. So how about the impact?

In the short run, the timing has run smack dab into current events, he said.

“Bad luck means that the encyclical is coming out on the day of Michael Jackson’s
funeral. No one will be paying attention,” he said.

And in the long run? Even if the encyclical itself changes no minds, he said, it could open up the substantial administrative power of the Catholic Church to working harder for the causes Benedict mentions. Priests and nuns working as organizers, parish halls for meetings, topics for homilies – these could make a difference in the long run.

“You might call this the ‘trickle down theory of papal encyclicals,'” he said.

Nancy Ammerman, sociology professor at Boston University, points to recent American history for an example of how official religious pronouncements reorganized a denomination’s work and, to some extent, the beliefs of the people in the pews.

“Think about what has happened to the SBC in the last 20 years. When sermons and Sunday School lessons every January always turn to the “sanctity of life” (and dozens of other similar emphases are present throughout the denomination), the culture and constituency of the denomination slowly comes to reflect those resolutions that weren’t supposed to have any official ‘clout.'”

(On the other hand, some sociologists think the Southern Baptist Convention’s aggressive push to the right helps explain the rise in the “None of the Aboves,” as people on the relative fringes of faith who disagreed with the SBC voted with their feet and left organized religion behind altogether.)

Is there any data showing whether papal pronouncements jiggle the needle of public opinion or behavior? John Green is a senior fellow in religion and American politics at the Pew Forum on Religion & Public Life and has done as much slicing and dicing of survey data about politics and faith as anybody alive. His answer?

“I am not sure there is systematic survey data on these issues.”

Hm. Then let’s look at the recent historical record to see whether we can find indications of where a pope’s statements have mattered.

You can take a look at what he found at the link.