In the dense, damp forests northeast of Houston, a pair of brothers hit on a viable real estate business model: Offer plots of cheap land and unconventional loans for people who wanted to build their own houses, with few restrictions.

The concept took off, not least among the large population of immigrants lacking permanent legal status in Texas, who often do not have the legal paperwork needed for most bank loans.

The Colony Ridge community, whose first residents moved in a decade ago, is now home to 40,000 people or more, with plans to more than double in size.

Over the years, its swift growth and predominantly Hispanic population drew opposition from the mostly white residents of a small nearby town and some local officials, who lodged complaints and filed lawsuits. Opponents spray-painted “Build that wall” on one of the developer’s billboards after Donald Trump’s election. One sent a desiccated chicken foot — and a note describing a voodoo hex — as a warning to the county judge.

But with a new wave of migrants arriving at the southern border in recent weeks, the sprawling development has become a lightning rod for conservatives in the state and highlighted a growing tension within the Republican Party: those who focus on business freedom and others determined to control the border.