The Reagan administration and law enforcement were the big winners and civil libertarians and draft protesters the losers as the United States Supreme Court ended more than nine months of deliberations Thursday, issuing over the course almost 160 opinions.
The justices saved the so-called biggest - and most controversial - cases until the end, changing 70 years of criminal-justice procedures by adding what some call a ''good faith'' standard to help determine the admissibility of evidence in criminal trials and deciding that college students who refuse to register for the military draft can be denied federal aid.
By modifying, at least in part, long-established rules of evidence, the high court seemed clearly to spell out a new criminal-justice philosophy - one that has been slowly emerging in recent years under a conservatively bent court led by Chief Justice Warren E. Burger. It says rights of society at large should take precedence over that of those accused of crimes - particularly when public safety and the protection of victims is at stake.
This philosophy is shared by President Reagan. The administration's Justice Department has long lobbied for those things that the court ultimately decided by a 6-to-3 margin Thursday.
The exclusionary-rule change will now allow evidence gathered by police with defective court warrants to be admitted in court if it is determined that law-enforcement officials acted in ''good faith'' (firm belief that they were following proper procedures) in apprehending suspects. Heretofore, it could be disallowed.
''We conclude that the marginal or nonexistent benefits produced by suppressing evidence obtained in objectively reasonable reliance on a subsequently invalidated search warrant cannot justify the substantial cost of exclusion,'' Associate Justice Byron R. White wrote for the court's majority.
Mr. White continued: ''In the absence of an allegation that the magistrate (or judge) abandoned his detached and neutral role, suppression is appropriate only if officers were dishonest or reckless in preparing their affidavit (justifying the warrant) or could not have harbored an objectively reasonable belief (the necessary proof for a warrant existed).''
The court's ruling was not on its face as broad as some would have had it. The decision seemed to deal only with defective court warrants, saying nothing about individual rights and exclusion of evidence where searches, questioning of suspects, and arrests have been made without any warrant at all.
Despite possible narrow implications, however, court dissenters decried the ruling as devastating. Associate Justice William J. Brennan talked of ''strangulation'' of the exclusionary rule. ''It now appears the court's victory over the Fourth Amendment is complete,'' Mr. Brennan added.
The Fourth Amendment, in essence, protects individuals against unreasonable searches and seizures. In 1914, the Supreme Court carved out the exclusionary rule ostensibly to ward off possible police misconduct and punish its perpetrators via suppression of illegally gathered evidence or confessions.
Ironically, this device is seldom used in defense strategy. Some surveys show that the cases of only 2 to 3 percent of those accused of crimes are affected by excluding improper evidence. Nonetheless, in recent years law enforcement has charged that devices such as the exclusionary rule have given criminals the upper hand in the courts and often tied the hands of the police. And the Reagan administration, in its criminal-justice package now before Congress, is pushing for legislation allowing a ''good faith'' exception. Presumably, the court's finding will give impetus to proposed bills along these lines.
In its ruling on the draft Thursday, the court upheld a 1982 law that disqualifies students who fail to register for the draft from federal loans and grants, holding 6 to 2 that such a position does not inflict unconstitutional punishment.
Opponents of the law had said that the requirement that students attest they have registered is a form of coercive self-incrimination. It also constituted, they held, unfair ''double'' punishment - denial of federal aid along with possible arrest or fine for defiance of the requirement to register under selective service regulations.
Writing for the majority, Chief Justice Burger reasoned that ''conditioning receipt of . . . aid on registration is plainly a rational means to improve compliance with the registration requirement.''
He continued that the law ''also furthers a fair allocation of scarce federal resources by limiting aid to those who are willing to meet their responsibilities to the United States by registering with the Selective Service when required to do so.''
The court insisted that the purpose of the draft-status disclosure law - passed last year but held up until now by a federal judge in Minnesota who deemed it an impermissible form of punishment - was not to catch violators but to swell the rolls of registrants. EXCLUSIONARY RULE: Court ruled 6-3 that evidence obtained through defective court warrants, if sought and gathered in good faith, is admissible in court. MILITARY DRAFT: Court ruled 6-2 that federal government is within constitutional rights to deny loans and grants to male students who fail to register for the draft. POLICE SEARCHES: Court ruled 5-4 that police may conduct illegal raids so long as they believe a warrant will be issued eventually to legalize the search.