Here's a challenge -- and it's an important one. Read the following brief letter I received today, and come up with a succinct, convincing answer to it. The writer was referring to our full-page article about the Catholic governor of Kansas, who recently vetoed a bill regulating late-term abortions ("Catholic governor vetoes late-term abortion bill," May 11). Her spokeswoman told us that Sebelius was personally opposed to abortion, but was committed to "uphold[ing] current Kansas law."

Here's the letter I received, from a reader in Wichita, Kan.:

"I have no difficulty with our governor espousing her constituency's views publicly, while maintaining differing views privately. Politicians should not be expected to evaluate all proposed legislation according to their personal convictions.

"What if our governor were Islamic instead of Catholic?" the writer asks.

The implication with the latter question is that if we don't require politicians to keep their religious beliefs safely locked in a drawer, they may try legislating headscarves, or maybe statues of Mary in every front yard.

Nobody wants that. But abortion is clearly a different sort of thing. It does not take any religious belief to know that abortion is the taking of innocent human life.

So where do we draw the line? How comfortable can Catholic politicians or the rest of us be with our beliefs informing not only our personal, private lives but also our other daily interactions?

In this election season, it is crucial that Catholics -- both politicians and voters -- spend time pondering their responsibilities in the public square.

Lest it be forgotten, that was also one of the main themes of Pope Benedict XVI's visit to the United States earlier this year. On the South Lawn of the White House, with the president looking on, the pope praised our country's "patrimony of shared ideals and aspiration" built on the "self-evident" notion that all are created equal and are endowed by God with inalienable rights.

"As the nation faces the increasingly complex political and ethical issues of our time, I am confident that the American people will find in their religious beliefs a precious source of insight and an inspiration to pursue reasoned, responsible and respectful dialogue in the effort to build a more humane and free society," the pope said.

But what does that mean in concrete, daily living? Let me know how you see the answer, by writing, or emailing (And let me know if you're willing to let me publish your answer.) I look forward to hearing from you.