In other rulings: city can require permits for rallies; federal agency can intervene on disabled worker's behalf.
In a decision with important implications for the war on terrorism, the US Supreme Court has made it easier for federal agents acting on a series of hunches to lawfully stop and search those they consider possible criminal suspects.
In a unanimous Fourth Amendment decision yesterday, the high court ruled that judges should grant law-enforcement officials significant leeway when the agents' experience and observations suggest that someone may be engaged in criminal activity.
Judges must consider the "totality of the circumstances" when determining whether an agent acted with reasonable suspicion, the court ruled.
The high court also unanimously upheld a Chicago Park District permit requirement for public demonstrations, in a key First Amendment decision. And the court ruled 6 to 3 in a discrimination case that the Equal Employment Opportunity Commission is not barred from filing its own lawsuit in a disability case, even when an employer and employee have agreed to settle any work-related claims via binding arbitration.
The Fourth Amendment case involved the Border Patrol arrest of Ralph Arvizu, who was stopped while driving on an unpaved road in a remote area of southeastern Arizona. Mr. Arvizu's minivan triggered remote sensors set up by agents to detect possible alien smugglers.
When a Border Patrol agent began following the van, he noted that Arvizu did not look at him and seemed stiff. The agent also noticed that the knees of two children sitting in the back of the van were unusually high, as if something was lying on the floor below them.
In addition, at one point the children in the van put their hands up at the same time and began to wave at the agent - yet continued to look forward.
The agent suspected that the children were being instructed to wave.
The agent pulled the van over and discovered 128 pounds of marijuana in duffel bags on the floor.
Arvizu was charged with possession with intent to distribute marijuana. In a pretrial motion, he moved to suppress the evidence, arguing that the Border Patrol agent did not have reasonable suspicion to stop his car.
The Ninth Circuit US Court of Appeals agreed with Arvizu, saying he needed more concrete indications of wrongdoing. In its decision on Tuesday, the high court reversed the Ninth Circuit.
"We think the approach taken by the court of appeals here departs sharply from [earlier Fourth Amendment cases]," writes Chief Justice William Rehnquist for the court.
The decision comes at a time when federal and local law-enforcement agents throughout the nation are on alert for possible terrorist activity. It will make it somewhat easier for law-enforcement officials to take quick action in the face of possible criminal activity.
The Chicago park decision, meanwhile, marks an important First Amendment decision, because it offers cities that are seeking to rein in large demonstrations a means to control such demonstrations without violating constitutional safeguards.
The high court ruled that requiring a permit to hold a demonstration in a public place does not necessarily amount to an unconstitutional attempt by city officials to censor free speech.
Instead, the court ruled that when the permit scheme regulating use of a public area is carried out in a neutral way, it does not violate First Amendment protections.
"Regulations of the use of a public forum that ensure the safety and convenience of the people are not inconsistent with civil liberties but are one of the means of safeguarding the good order upon which civil liberties ultimately depend," writes Justice Antonin Scalia for the court.
The case had raised questions about whether the city had denied a park demonstration permit because it disagreed with the political views of those seeking to hold the demonstration. Justice Scalia acknowledged the issue in his decision, but found that Chicago's permit system was applied neutrally.
In the discrimination case the Supreme Court ruled yesterday, the justices clarified the reach of the Equal Employment Opportunity Commission - and in effect curbed the ability of employers to keep workplace disputes out of the courts.
The decision means that in some cases, the EEOC can circumvent an arbitration agreement and do for an individual wronged worker what the worker is unable or perhaps unwilling to do for himself.
The case involved a short-order cook, Eric Baker, who was fired from a Waffle House restaurant in West Columbia, S.C., after he had a seizure on the job. Mr. Baker had agreed when he was hired that any work dispute would be resolved by arbitration.
Such arbitration agreements cover an estimated 10 percent of the American workforce, and are increasingly popular with employers. Many of those covered by the agreements are low-wage workers like Baker.
Mr. Baker has a seizure disorder as a result of an automobile accident. After the seizure on the job in 1994, he was quickly fired for what Waffle House said were his own safety and the good of the restaurant.
Instead of arbitration, Baker took his case to the EEOC, which sued in federal court for what it called a violation of the Americans With Disabilities Act.
Material from Associated Press was used in this report.