BY DANIEL A. GRECH

  BUENOS AIRES - Abandoned by long-time allies and facing impeachment by Congress, the head of Argentinas Supreme Court resigned Friday in a major political victory for President Néstor Kirchner.

  Kirchner had pressed hard for the resignation of court president Julio Nazareno as part of sweeping changes instituted in his first four weeks in office. And he had called for Nazareno's resignation as a critical step in restoring public faith in the heavily politicized and widely discredited Supreme Court.

  Nazareno, a close ally and former law partner of former President Carlos Menem, was part of the courts so-called automatic majority, whose favorable rulings paved the way for Menem's privatization of state-owned firms in the 1990s. The court also frequently intervened on behalf of Menem and his allies -- for example, in 2002 clearing Menem, then under house arrest, of involvement in an arms-sale scandal.

  Kirchners successful campaign to remove Nazareno has been criticized by some legal experts as an inappropriate imposition of executive power on the judicial branch.
  Secretary of State Colin Powell, during a brief visit with Kirchner earlier this month, emphasized any judicial reform must take place within the countrys Constitution.

  ''I think the whole thing is a tragedy,'' said Martín Bhmer, dean of the University of Palermo law school in Buenos Aires and an advocate of judicial reform. ``Its bad that the executive put so much pressure to change the judiciary. But its difficult to defend a Supreme Court that has acted in the way it has.''

  Kirchner, who came to office with just 22 percent of the vote, has received enormous public support for his reform efforts. Some recent public opinion surveys show his approval rating at close to 70 percent.