The red, white and blue has flown outside LaPoynor High School in LaRue, Texas for as far back as anyone can remember.
But instead of 50 stars on a blue field, this flag bears a cross - a symbol of the Christian faith.
And that's a big problem for a bunch of out-of-town atheist agitators -- a mighty big problem.
The Freedom From Religion Foundation, a Wisconsin-based group of atheists, agnostics and freethinkers, sent a letter to the local school district demanding the flag be removed.
"It is unconstitutional for the school to display the Christian flag," FFRF attorney Sam Grover wrote to Supt. James Young. "The display of this patently religious symbol by the District confers government endorsement of Christianity, in violation of the Establishment Clause."
The perpetually offended atheists told the school district they must be inclusive to minority religions and non-religious people.
"The District must immediately remove the Christian flag from school grounds," Grover wrote. "In addition, the District must ensure that its staff members are not organizing, promoting, or participating in religious events while acting int heir official capacities."
The school superintendent told local news reporters they were reviewing the demand letter - but have yet to make any sort of announcement.
But while the adults in LaPoynor wrangle over what to do -- students at the high school have taken matters into their own hands -- they've decided to stand up to the atheists.
Several youngsters purchased Christian flags and mounted the banners on their pickup trucks. It was quite a scene in the high school parking lot -- a convoy of trucks adorned with the Christian flag -- waving in the Texas breeze.
"They can try to take it, but we're going to fight for it," junior Jared Sanchez told Nexstar Broadcasting.
And at a recent school board meeting, local residents offered their two-cents worth.
“The Freedom From Religion organization really has a distorted and inaccurate view of the separation of church and state in the First Amendment,” one resident told television KLTV. “Matter fact I'd like to say that their viewpoint is probably void and alien to that of our founding fathers."
It sounds like there are lots of great patriots in LaPoynor -- young and old -- and reckon those Wisconsin atheists are about to learn why it's best not to mess with Texas.