It has to do with the forces driving the decision the Supreme Court made in Brown v Board of Education. The authors argues that this marked a turning point where an interest group could use the courts to change policy - something that no other liberal democracy allows. Changes in public policy that interest groups are able to achieve by going around the legislature, straight to the court:
One of the great turning points in 20th-century American history was the Supreme Court’s 1954 Brown v. Board of Education decision, which overturned on constitutional grounds the 19th-century Plessy v. Ferguson case that had upheld legal segregation. This decision was the starting point for the civil rights movement, which, over the following decade, succeeded in dismantling the formal barriers to racial equality and guaranteed the rights of African Americans and other minorities. The courts had cut their teeth earlier over union organizing rights; new social rules based on those rights provided a model for subsequent social movements in the late 20thcentury, from environmental protection to women’s rights to consumer safety to gay marriage.
So familiar is this heroic narrative to Americans that they seldom realize how peculiar it is. The primary mover in the Brown case was the National Association for the Advancement of Colored People (NAACP), a private voluntary association. The initiative had to come from private groups, of course, because state governments in the South were controlled by pro-segregation forces. The NAACP pressed the case on appeal all the way to the Supreme Court. What was arguably one of the most important changes in American public policy thus came about not because Congress, as the representative of the American people, voted for it but because private individuals litigated through the court system to change the rules. Later developments, like the Civil Rights and Voting Rights Acts, were the result of congressional action, but even in these cases enforcement was carried out by courts at the behest of private parties.
No other liberal democracy proceeds in this fashion. All European countries have gone through similar changes to the legal status of racial and ethnic minorities, and women and gays in the second half of the 20th century. But in Britain, France or Germany, the same results have been achieved through a national justice ministry acting on behalf of a parliamentary majority. The legislative rule changes might well have been driven by public pressure, but they would have been carried out by the government itself, not by private parties acting in conjunction with the judiciary.
This something to file away and think about more when we cover both civil rights and interest groups later this 3 week term.