Spain's 11-month-old Socialist government may have been resorting to ''dirty tricks'' or illegal acts to combat Basque terrorists operating out of France. Guerrillas of the terrorist organization ETA have been able to strike in Spain and escape to France, where they live with complete immunity to Spanish justice.
Last week's killing of Army Capt. Martin Barrios coincided with the arrest in France of four Spanish police officers on a secret mission and with the disappearance of two ETA leaders in France.
The Spanish police were arrested by the French after they apparently bungled an attempt to kidnap an exiled ETA leader, Jose Maria Larretxea. The Spanish police are in French jails awaiting trial for premeditated beatings while Spanish diplomats lobby for their release.
The affair provoked more scandal for its clumsiness than for the policy of secret missions. Popular tabloids complained about the ''keystone cops'' adventure.
French Interior Minister Gaston Defferre wrote to his Spanish colleague, Jose Barrionuevo, requesting ''more discretion and professionalism'' of Spanish police in French territory, according to police sources here.
''You are walking on quicksand,'' warned Communist representative Santiago Carrillo in parliament, while opposition leaders supported the legitimacy of secret missions in France. On television Mr. Barrionuevo denied intentions of ''dirty warfare'' but said secret missions to gain information about ETA guerrillas in France would continue and are legitimate.