WHEN Kevin S. and his wife separated two years ago, they agreed to a custody arrangement that seemed workable. Their two young children would live with their mother in the family's suburban home, then spend alternate weekends and Wednesday evenings with their father.
The agreement hasn't worked. Sometimes the children's mother calls to cancel a visit, offering reasons ranging from skating lessons to a child's stubbed toe. At other times, when Kevin arrives at the agreed time, the house is dark. When he tries to telephone his children, he gets the answering machine.
''There's always one excuse or another,'' says Kevin, who asks that his full last name not be used, because the divorce is not final and he fears retaliation. ''I've been to court many times. It's expensive financially, but it's expensive emotionally too.''
Call them ''driven-out dads,'' ''disenfranchised fathers,'' or ''displaced parents.'' They are divorced or separated parents, women as well as men, whose former spouses block access to their children despite court-ordered visiting schedules. The emotional cost is often accompanied by an economic one.
Jeffrey Leving, a Chicago attorney who specializes in such cases, calls it ''visitation abuse.'' Although no statistics exist on the number of fathers who are ''involuntarily excluded from the family unit,'' as he puts it, he sees such cases increasing. Noncustodial mothers, whose ranks are far smaller, face similar problems.
''Courts are very aggressive in enforcing child support, but when it comes to enforcing visitation, they are very lax,'' Mr. Leving says. ''Stereotypically, fathers are not seen as being needed emotionally in the parenting process. Stereotypically, they are considered breadwinners, and their job is to earn money and support the family.''
Yet As a result, Leving says, angry divorcing parents ''know they can ignore visitation and get away with it.''
In January 1994, a pioneering law took effect in Illinois, making it a crime to block a noncustodial parent's visitation rights. Under terms of the Unlawful Visitation Interference Law, the first two violations are petty offenses. The third becomes a misdemeanor. The measure also covers grandparents' visits, which are sometimes interrupted or denied after a divorce.
Republican State Rep. Cal Skinner Jr., who sponsored the bill, sees the law as an ''educational tool.'' He says, ''It's not about putting people in jail or fining people. It's about telling people that society thinks it is important that children have access to both parents, even if the parents hate each other.''
In Representative Skinner's view, no-fault divorce has contributed to an increase in visitation problems. ''I believe couples fight over kids more than they used to,'' he says. ''They used to fight about the question, 'Do I have a reason to get a divorce -- infidelity or whatever?' Now they fight about the kids.''
A report released two weeks ago by the Illinois State Police shows that in 1994, 411 visitation complaints were filed. Of those, 365 were classified as actual offenses.
Even so, the law does not always translate into support from police officers around the state. Often they want such cases returned to civil court, according to Skinner and other advocates.
Andy Knott, a spokesman for the Cook County State's Attorney's Office in Chicago, faults the state's measure as a ''get-a-free-attorney law,'' because it enables private parties to use local prosecutors to enforce visitation decrees. Explaining that the state attorneys' association wants to have the law repealed, he says, ''A private attorney is more appropriate to enforce an agreement that people negotiated with a judge in the first place.''
In rural, less-populated counties, Mr. Knott says, state's attorneys complain that they sometimes find two or three parents ''sitting on their doorsteps on Monday morning seeking to have them go to court to fix visitation arrangements that have gone awry over the weekend. It is a huge manpower drain for those state's attorneys.''
Yet when the law is enforced, it does help noncustodial parents, advocates say.
One success story comes from Roxann Valenta of Cedar Lake, Ind., whose former husband received custody of their daughter, now 10. He and the child live just across the state line in Crete, Ill.
''For six years I saw her only two or three days out of the year,'' Ms. Valenta says. ''I would call to come over to visit, but he kept refusing.''
Desperate, she sought help regularly from Crete police. ''They told me I had to take him back to court -- there was nothing they could do,'' she says. ''Lawyers wanted $10,000 to $20,000, and I couldn't afford that.''
Then last year, when Valenta told the police about the new Illinois law, everything changed. The next time she tried unsuccessfully to see her daughter, she says, officers took out a warrant for her former husband's arrest.
''Since then, he absolutely has not refused me any visitation at all,'' she adds. ''The law does work. It helps the police too. They don't have this hysterical woman coming in every other weekend crying, 'Please, could you help me?'''
For Chris Boehm, an architect in Chicago who has been separated from his wife for three years, there has been no such gratifying resolution.
Despite a court-arranged visitation schedule, Mr. Boehm's last regular visit with his 12-year-old daughter and 11-year-old son was a year ago. His estranged wife alleged that he had abused one of the children -- a charge the Illinois Department of Children and Family Services investigated three times and found to be false. Yet he has been unable to regain his visitation rights.
''If you want to get revenge, just cry abuse,'' he says. ''I have an outstanding court order that allows visitation, but she refuses to honor it.''
''I'm really just appalled at the way the court system doesn't work,'' Boehm continues. ''I'm sure there are convicted felons who get to see their kids, but I don't. It gets harder as time goes by. And you don't know how hard it is to write out the [child-support] check some weeks, but I do it. I figure this is not the kids' fault.''
The attorney representing his wife declined to comment because the case is still in litigation.
For now, Boehm has decided not to pursue attempts to see his children. ''I don't think this struggle is good for the kids,'' he says. ''I haven't given up, but I'm taking the long-term view. My kids are just about teenagers, and they may start to question what's going on and want to see me. I really think that's the way to solve this. The court doesn't want to solve this problem for me.''
Kevin shares that frustration. ''I feel I have nowhere to turn,'' he says.
Outlining his ideas for change in the legal system, Leving says, ''We're going to need more laws. But more than new and stronger laws, we're going to need judges who are educated on issues like these. State-court judges in the divorce division are more important than federal-court judges, because their decisions are molding the futures of minor children who will grow up to be the backbone of this country.''
Summing up his hopes, Leving says, ''Courts should never be pro-male or pro-female. Courts should be pro-child.''