The pipe organ at the First Baptist Church in Robert, La., erupts into "The Wedding March." The bride, Erlene Thompson, is a little nervous. She need not be: She has known the gray-haired groom for most of her life. More precisely, she has been married to John Thompson for the last 37 years. Together they have raised four children, who have given them eight grandchildren and one great-grandchild-an infant boy whom Erlene cradles in her arms as she steps down the aisle. "The vows this time were a lot more meaningful to both of us," she says later. "It just runs much, much deeper."

The Thompsons, however, didn't just renew their vows. They rewrote them, based on the state's new, tough-minded marriage law. Following a brief ceremony, they and more than two dozen other couples from their church signed a legally binding agreement, witnessed by a state notary, pledging "to take all reasonable efforts" to preserve their marriage unto death.

The Louisiana Covenant Marriage Act, passed into law last August, remains controversial, and with good reason: It is the first experiment in raising both the entrance and exit requirements for marriage since the no-fault divorce revolution began in the 1970s. On the front end, it requires premarital counseling. On the back end, it limits the legal grounds for divorce to adultery, felony conviction, abandonment, physical or sexual abuse, or separation of at least two years. It also requires that struggling couples get counseling before they may call it quits.

Here's the part that puts choice-loving liberals in a quandary: The covenant contract is purely optional. By leaving the existing no-fault regime untouched, Louisiana has created the nation's first two-tier marriage system. The message to couples contemplating the strength of their marital commitment: You choose-decaf or double espresso.

Hundreds of congregations throughout the state have called the office of Louisiana state representative Tony Perkins, who sponsored the legislation, to request information on the law. Over the last six months, thousands have converted to covenant arrangements. Thousands more are expected to follow suit this month in ceremonies across the state. Meanwhile, legislatures in nearly two dozen states are considering covenant-style reforms.

Making a lifelong commitment is one thing, of course. Keeping it often requires help. Supporters say one of the law's most important dictates is that struggling couples must agree to counseling before they can take steps toward dissolving their union.

People can choose either religious or secular mediators, but either way they'll be read the riot act. The law obligates them to talk frankly about their marital responsibilities as spelled out in their marriage license and in the Marriage Covenant Act, a pamphlet prepared by the state's attorney general.

Some newlyweds are, in fact, banking on tough medicine to help get them through the hard times. Ben and Jennifer Ramagos-Young had both been married and divorced before they met. When Jennifer told her attorney she was getting married again, this time under the covenant contract, the attorney tried to talk her out of it. But Jennifer insisted. "Slowing things down," she says, "will allow us to get the counseling we both may need before we make a rash decision." Buying time is often exactly what marriages in crisis need: better for couples to be talking, even through clenched teeth, than consulting with divorce lawyers.

Under the new law, an abused spouse can still escape the relationship with relative ease. But for couples simply drifting apart, the law's two-year waiting period-rather than six months under no-fault-gives them a chance to work things out. "We're not erecting a barricade," Rep. Perkins says. "We're just putting in some speed bumps."

Studies show that couples who undergo counseling are likely to navigate the storms of conflict and stay afloat. University of Denver psychology professor Howard Markman has summarized 17 studies of the impact of counseling on marital satisfaction. He found that nearly three out of four distressed couples who got help reported significant improvement in their relationships. If Mr. Markman is right, then divorce may be avoidable far more often than we think. For one thing, most breakups are not driven by extreme abuse: About two-thirds result from "low-level conflict" in which couples slowly drift apart. Second, in most cases the decision to separate is not mutual.

This suggests that the key to rescuing failing marriages is to address issues of commitment and character, a process best tackled with extended, roll-up-your-sleeves counseling. No-fault divorce short-circuits this process.

But the most controversial part of the Louisiana experiment is its return to a fault-based system for divorce-the same system discarded by the no-fault revolution. Critics claim that reintroducing fault would only fuel hostilities in failing marriages. But others point out that fault has not really disappeared from divorce proceedings, it just insinuates itself into battles over alimony payments, division of property, and child custody.