Explain the difference between judicial restraint and judical activism?

Judicial restraint limits the powers of judges to strike down a law. As opposed to the progressiveness of judicial activism, judicial restraint opines that the courts should uphold all acts and laws of Congress and legislatures unless they oppose the United States Constitution.

Judicial activism is the view that the Supreme Court and other judges can and should creatively (re) interpret the texts of the Constitution and the laws in order to serve the judges' own visions regarding the needs of contemporary society. Judicial activism believes that judges assume a role as independent policy makers or independent "trustees" on behalf of society that goes beyond their traditional role as interpreters of the Constitution and laws. The concept of judicial activism is the polar opposite of judicial restraint.

Judicial restraint refers to the doctrine that judges' own philosophies or policy preferences should not be injected into the law and should whenever reasonably possible construe the law so as to avoid second guessing the policy decisions made by other governmental institutions such as Congress, the President and state legislatures. This view is based on the concept that judges have no popular mandate to act as policy makers and should defer to the decisions of the elected "political" branches of the Federal government and of the states in matters of policy making so long as these policymakers stay within the limits of their powers as defined by the US Constitution and the constitutions of the several states.