As an evangelical Christian, I can see at least three reasons why Pope Francis and his six-day visit to our nation should matter to all Americans, not just Catholics.

First, the pope matters because he represents half of the world’s 2.18 billion Christians. And he reminds us that no other religion comes close to matching Christianity’s vast geographical, cultural and racial diversity. According to the Pew Research Center: “Christians are … so far-flung, in fact, that no single continent or region can indisputably claim to be the center of global Christianity.” For that reason, no Grand Mufti or Grand Ayatollah, no Chief Rabbi, no Dalai Lama, can hope to travel the four corners of the world and elicit the kind of superstar-like greeting that is accorded to a Pope Francis or a Billy Graham.

Second, Francis matters because he reminds us that the pope is not only a head of state – Vatican City is the smallest independent nation in the world but also one of the most influential – he is also meant to be a pastor. And no other pontiff in my lifetime has shepherded his planet-wide flock as humbly, tenderly, or cheerily as Francis.

Pope Francis reminds everyone that we Americans aren’t the center of the universe – gasp! – but that we are a nation mightily blessed by a God who values a humble spirit and a hospitable heart.

Third, Pope Francis matters because he reminds us of how terribly divided we’ve become not only in the United States, but globally. Francis himself leans left in his severe upbraiding of wanton capitalism and his belief in manmade climate change. And he leans right in his unshakeable opposition to abortion and his defense of the Biblical definition of marriage, which is the consecrated union of a man and a woman. Yet he holds the two opposing views so sincerely and thoughtfully, and is so likeable in the process, that he makes it hard for the rest of us to go on demonizing our political opponents.

Still, he is vulnerable. Like Jesus.

In his day, Jesus was a study in sharp contrasts. In his zealous concern for the poor, he behaved like a true man of the people. But in his seeming inattention to the atrocities being committed by the Roman Empire, which in Jesus’ time was at the height of its awful power, he came across as indifferent to the political plight of his fellow Jews.

The Bible reports that Jesus enjoyed a three-year honeymoon, during which he played to enlarging, adoring crowds of poor and oppressed Jews. They cheered him on, followed him everywhere, as he performed miracles and called out the Temple leadership for their arrogance and hypocrisies.

But then they all turned on him – the people, the Temple priesthood, the Roman government – and he ended up being crucified. He was a sinless man who preached love and forgiveness, but everyone turned on him when they discovered he was not everything they wanted him to be.

Pope Francis is now smack in the middle of the third year of his papacy’s honeymoon period. He is hugely popular because he comes across as a man of the people, an unpretentious servant of God who clearly loves the down-and-out exceedingly more than he does the stuffy, pompous trappings of his office. It’s no wonder President Obama is going to meet him at the airport immediately upon his arrival – who wouldn’t want Francis on his team?

But what will happen to Francis’s popularity if he uses his visit to the Democrat-controlled White House tomorrow to reiterate – albeit lovingly – his hardline stand against abortion and gay marriage? President Obama has reportedly invited to the reception a handful of LGBT activists antagonistic to the Catholic church. And what will happen to the pope’s soaring popularity if he uses his visit to the Republican-controlled Congress on Thursday to sound off about manmade climate change? Many conservative members of the House and Senate fervently cite scientific evidence that climate change is mostly natural.

In short, how popular will this Jesus-like Francis be when liberals and conservatives are reminded that he is not everything they want him to be?

Having said that, I believe that even if the pope’s popularity takes a hit after this revealing, first-ever, up-close-and-personal time with us here in the United States, the richest nation in the world, it’s fairly certain he will continue being enormously well-liked globally, where poverty is the norm.

That’s the final, important reason why Pope Francis should matter to us. He reminds everyone that we Americans aren’t the center of the universe – gasp! – but that we are a nation mightily blessed by a God who values a humble spirit and a hospitable heart. Heavenly qualities that I expect and pray will be greatly in evidence during the next six exciting days.

Michael Guillen was born in East Los Angeles, earned his B.S. from UCLA and his M.S. and Ph.D. from Cornell University in physics, mathematics and astronomy. For eight years he was an award-winning physics instructor at Harvard University. For fourteen years he was the Emmy-award-winning science correspondent for ABC News, appearing regularly on "Good Morning America," "20/20," "Nightline," and "World News Tonight." Dr. Guillen is the host of the History Channel series, "Where Did It Come From?" and producer of the award-winning family movie, "LITTLE RED WAGON." His latest best-selling book, Amazing Truths: How Science and the Bible Agree, is published by HarperCollins. For more information, visit his website: www.michaelguillen.com.