SIOUX CENTER, Ia. — Here’s a little secret about the police chief of this picturesque town in rural northwest Iowa. He doesn’t lock his back door.

If the plumber comes when no one is home, Paul Adkins tells him, “Yep. Go on in.”

Lots of other residents leave their houses unlocked, and their cars, too.

Tucked into the northwest corner of Iowa, where in late summer green oceans of corn stretch as far as the eye can see, Sioux Center, population 7,389, is that kind of quaint Midwestern farming community. The city’s immaculate appearance is worthy of a movie set, with street after street lined with stately older homes and manicured lawns.

For decades the demographics of this bastion of Reformed Christians of Dutch ancestry could be summed up in three words: White. Conservative. Republican.

Mitt Romney won 83 percent of the vote here in 2012.

But like many small towns in Iowa, this once homogeneous community is quickly changing. The Hispanic population in Sioux Center has more than tripled since 2000. One in seven Sioux City residents is now Latino.

...many Republicans in this part of Iowa wish candidates would talk more about the contributions of immigrants, both legal and illegal, and fixing the nation’s broken immigration system and less about building walls and deporting people.