During the first years of the Roberts court, it has consistently ruled in favor of corporate power, such as in holding that corporations have the 1st Amendment right to spend unlimited amounts in independent political campaigns. For the first time in American history, the high court has struck down laws regulating firearms as violations of the 2nd Amendment and held that the Constitution protects a right of individuals to possess guns. It has dramatically cut back on the rights of criminal defendants, especially as to the exclusion of evidence gained through illegal searches and seizures under the 4th Amendment and the protections of the 5th Amendment’s privilege against self-incrimination. It has greatly limited the ability of the government to formulate remedies for the segregation of public schools. It has significantly expanded the power of the government to regulate abortions.

As always, the composition of the court is a product of historical accident and presidential elections. From 1968 to 2009, there were only two Democratic appointees to the Supreme Court, Ruth Bader Ginsburg and Stephen G. Breyer, in part because President Carter is one of the few presidents who did not get to fill a vacancy. Republican Presidents Nixon, Ford, Reagan and both Bushes had a total of 12 vacancies to fill, and their picks included four staunch conservatives who are now on the court: Roberts, Antonin Scalia, Clarence Thomas and Samuel A. Alito Jr.

On the issues that today define the ideological continuum, these four justices are as conservative as any in American history. Their views are best understood far more by reading the 2008 Republican Party platform than by studying the views of the Constitution’s framers.

If the court is split 5 to 4, as it often is in the most high-profile and important cases, these four justices can usually count on being joined by Justice Anthony M. Kennedy. Last term, for example, there were 12 cases in which Roberts, Scalia, Thomas and Alito were on one side, with Stevens, Ginsburg, Breyer and Sonia Sotomayor on the other. Kennedy sided with the conservatives in nine of these cases and with the liberals in only three. Similarly, the year before, there were 16 decisions that were split 5 to 4 along ideological lines, and Kennedy sided with the conservatives in 11 and with the liberals in five. During the five years of the Roberts court, Kennedy has been with the conservatives more than twice as often as with the liberals in ideologically split 5-4 decisions.

It is easy to lose sight of how successful conservatives have been in changing constitutional law. Each individual decision only gradually changes the law. Conservatives have not prevailed in every decision of the Roberts court. In some areas, the conservative agenda hasn’t succeeded: It has not overruled Roe vs. Wade or declared all affirmative action to be unconstitutional. But it is wrong to generalize from these areas and to miss the overall conservative impact on constitutional law.

There is no reason to think that this term will be any different as the court considers major issues concerning the separation of church and state, the ability of states to regulate immigration and the rights of criminal defendants. And in the following term or two, the court will be asked to consider major issues such as the constitutionality of the federal healthcare bill, the ban on marriage equality for gays and lesbians, and Arizona’s law requiring state and local police to enforce federal immigration laws. The healthcare litigation, which is now pending in federal District Courts, will provide the best sense of whether this court will return us to the 1930s, when five conservative justices struck down many federal laws adopted as part of the New Deal.

The court’s conservative majority could last another decade no matter who wins the White House in the next presidential elections. Absent unforeseen circumstances, Roberts, Alito, Thomas, Scalia and Kennedy will likely be on the court beyond when President Obama leaves office, even if he is a two-term president.

It is a court for conservatives to rejoice over and liberals to bemoan. And it is likely to stay that way for years to come.

Erwin Chemerinsky is dean of the UC Irvine School of Law and the author of the forthcoming book, “The Conservative Assault on the Constitution.”