Congress often takes its time to come around to an idea that others have long before concluded makes sense. And sometimes it never does, chiefly when ideology is allowed to trump logic.

It’s just possible, though, that lawmakers may be poised to tear down a decades-old system for financing student loans that was built on an ideological principle that really can’t withstand close scrutiny, and replace it with one that saves dollars and makes sense.

Two weeks ago, the House Education and Labor Committee, with the strong encouragement of the Obama administration, took a step toward ending the false premise that private lenders are full partners in the federally subsidized college loan program. If a bill approved by the committee becomes law, private lenders will be cut out of this program and will have to stop dining at their taxpayer-provided trough.

This program has evolved into a primary source of support for college students. Everyone seems to agree that it is a necessary function of government to help middle-class families cope with the rising cost of higher education. But most people probably don’t know how the loan program works. And until recently, that was possibly true for most lawmakers.

For the past 15 years, this has been a two-pronged operation. Colleges decided whether they wanted to have their students take out loans straight from the Department of Education through college financial aid offices, or whether they wanted students to borrow from banks and other traditional private lenders. Most chose the latter.

The lenders have held up the pretense that they provide better service than does an arm of the federal government and that there are actually differences among bank loans, so that students stand to benefit by picking one over the other.

Sorry, but that notion is a sham. Congress has long required that the terms of these loans be identical, regardless of whether they are issued by the government or a private lender. It doesn’t matter to the student where the money comes from — the dollar amounts, the interest rates and even the repayment terms are virtually the same.

For taxpayers, though, there is a difference, and it’s a big one. In the case of presumed “private” loans, the government pays more than it does for “direct” loans — billions of dollars more — because it guarantees the principal amount and it promises a minimal return to the lender. Banks are supposed to be compensated for taking risks, but in the case of government-subsidized student loans, they incur almost no risk. Yet they get compensated anyway.

Moreover, there’s ample evidence that some private lenders have engaged in questionable or worse behavior to persuade colleges to funnel student borrowers their way. When money is free, people will do all sorts of things to get their hands on it. And that raises questions about why lawmakers would want to perpetuate a system that promotes graft, as well as waste.

No Benefit to the Gravy Train

There is an ideological argument to be made against almost any government-run loan program. It’s always true that the Treasury can borrow more cheaply than a private lender, and that makes the cost of loans made by the government inherently less for the borrower. But private lenders are the backbone of the American economy, and it’s an article of faith in many corners that the government shouldn’t be in the business of lending directly to consumers if banks and other financial institutions can fill the bill.

That said, Republicans and Democrats alike decided long ago to subsidize student aid and to set the terms of basic loans to pay for college, undercutting any argument from ideologues against government involvement. On top of that, how can anyone rail about welfare for troubled banks and then conveniently overlook the fact that the private student loan system is a gravy train for lenders with essentially no added benefit for borrowers?