Back when Louisiana politicians launched TOPS a generation ago, they probably had no idea they were creating a monster.

That’s not to say it’s a bad thing. The Taylor Opportunity Program for Students — named for late oilman Patrick Taylor, whose privately funded promise to help high-performing poor students attend college inspired the sprawling, state-funded higher education scholarship program — has provided more than $2 billion to educate many thousands of Louisiana students.

What’s scary about TOPS is that, as it now stands, there doesn’t seem to be a way to bring its cost under control.

You could blame the program’s appetite for scarce state resources on its success. TOPS, which has quintupled in its annual price tag since 1998, is widely used and wildly popular — so popular that some politicians consider it untouchable even in desperate budget times. Even those willing to consider adjustments to rein in costs, or at least slow their growth, approach the issue with extreme care.

You could blame it on the state’s disinvestment in direct aid to public institutions, which has resulted in steep tuition increases. TOPS scholarships are designed to cover full tuition (but not also-escalating student fees), so when the cost of tuition rises, so does the cost of each scholarship. Last year, a legislative effort to keep TOPS payouts from automatically increasing every time tuition goes up was vetoed by former-Gov. Bobby Jindal, despite support from Taylor’s widow Phyllis and warnings that the program was becoming unsustainable.

But just as much of the fault lies in TOPS’ muddled public purpose.

What started off as an effort to level the playing field for students who wouldn’t otherwise be able to afford college has morphed into a merit-based entitlement used more widely by the middle class. Income restrictions went by the wayside in 1998, and rising tuition has made the scholarships even more attractive to families of means than before. From 2003 to 2014, more than half the 167,402 students on TOPS came from families with incomes of $70,000 or above, and nearly 14 percent had parents who made more than $150,000. Fewer than 16 percent came from families whose incomes put them below the poverty line.

A broader byproduct is a disparity in how the program affects the state’s schools. LSU has seen its ambitious Flagship Agenda fall by the wayside, but because so many of its students qualify for TOPS, it’s been shielded from the worst of the budget cuts. The state’s historically black colleges, which tend to serve the same underprivileged population Taylor first targeted for aid, are struggling mightily, as are many of the students who are trying to meet higher tuition payments without the aid of TOPS.

One argument for keeping TOPS purely merit-based is that it’s designed to prevent the best and brightest students from leaving Louisiana for better opportunities elsewhere. But the state has never measured whether it actually does that. And the goal has been watered down by standards that reward average as well as particularly talented students. Taylor’s original program demanded students maintain a 3.0 GPA, but the state lowered it to 2.5. There are arguments in favor of being more inclusive, but there are also real questions over whether taxpayers should foot the bill for C-plus students from well-off families while other programs are facing drastic cuts.

TOPS isn’t the only state program that’s proven hard to keep in check, even if the public return on investment is hard to quantify.

Many of the business tax exemptions in place have proven just as poorly designed and equally resistant to change. It’s always politically difficult to claw back government benefits once they’ve been granted, even when the state desperately needs to get its spending under control.

That’s why the explosive growth of TOPS should serve as a cautionary tale. When government sets out to do something good, it’s just as important that it gets it right.

Stephanie Grace can be contacted at sgrace@theadvocate.com. Follow her on Twitter, @stephgracenola.